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<div align="center">
<h1> 30 Days Of JavaScript: Tipos de Dados</h1>
<a class="header-badge" target="_blank" href="https://www.linkedin.com/in/asabeneh/">
<img src="https://img.shields.io/badge/style--5eba00.svg?label=LinkedIn&logo=linkedin&style=social">
</a>
<a class="header-badge" target="_blank" href="https://twitter.com/Asabeneh">
<img alt="Twitter Follow" src="https://img.shields.io/twitter/follow/asabeneh?style=social">
</a>
<sub>Author:
<a href="https://www.linkedin.com/in/asabeneh/" target="_blank">Asabeneh Yetayeh</a><br>
<small> January, 2020</small>
</sub>
</div>
</div>
[<< Dia 1](../readMe.md) | [Dia 3 >>](../03_Day_Booleans_operators_date/03_booleans_operators_date.md)
![Thirty Days Of JavaScript](../images/banners/day_1_2.png)
- [📔 Dia 2](#-day-2)
- [Data Types](#data-types)
- [Primitive Data Types](#primitive-data-types)
- [Non-Primitive Data Types](#non-primitive-data-types)
- [Numbers](#numbers)
- [Declaring Number Data Types](#declaring-number-data-types)
- [Math Object](#math-object)
- [Random Number Generator](#random-number-generator)
- [Strings](#strings)
- [String Concatenation](#string-concatenation)
- [Concatenating Using Addition Operator](#concatenating-using-addition-operator)
- [Long Literal Strings](#long-literal-strings)
- [Escape Sequences in Strings](#escape-sequences-in-strings)
- [Template Literals (Template Strings)](#template-literals-template-strings)
- [String Methods](#string-methods)
- [Checking Data Types and Casting](#checking-data-types-and-casting)
- [Checking Data Types](#checking-data-types)
- [Changing Data Type (Casting)](#changing-data-type-casting)
- [String to Int](#string-to-int)
- [String to Float](#string-to-float)
- [Float to Int](#float-to-int)
- [💻 Day 2: Exercises](#-day-2-exercises)
- [Exercise: Level 1](#exercise-level-1)
- [Exercise: Level 2](#exercise-level-2)
- [Exercises: Level 3](#exercises-level-3)
# 📔 Day 2
## Data Types
In the previous section, we mentioned a little bit about data types. Data or values have data types. Data types describe the characteristics of data. Data types can be divided into two:
1. Primitive data types
2. Non-primitive data types(Object References)
### Primitive Data Types
Primitive data types in JavaScript include:
1. Numbers - Integers, floats
2. Strings - Any data under single quote, double quote or backtick quote
3. Booleans - true or false value
4. Null - empty value or no value
5. Undefined - a declared variable without a value
6. Symbol - A unique value that can be generated by Symbol constructor
Non-primitive data types in JavaScript includes:
1. Objects
2. Arrays
Now, let us see what exactly primitive and non-primitive data types mean.
*Primitive* data types are immutable(non-modifiable) data types. Once a primitive data type is created we cannot modify it.
**Example:**
```js
let word = 'JavaScript'
```
If we try to modify the string stored in variable *word*, JavaScript should raise an error. Any data type under a single quote, double quote, or backtick quote is a string data type.
```js
word[0] = 'Y'
```
This expression does not change the string stored in the variable *word*. So, we can say that strings are not modifiable or in other words immutable.
Primitive data types are compared by its values. Let us compare different data values. See the example below:
```js
let numOne = 3
let numTwo = 3
console.log(numOne == numTwo) // true
let js = 'JavaScript'
let py = 'Python'
console.log(js == py) //false
let lightOn = true
let lightOff = false
console.log(lightOn == lightOff) // false
```
### Non-Primitive Data Types
*Non-primitive* data types are modifiable or mutable. We can modify the value of non-primitive data types after it gets created.
Let us see by creating an array. An array is a list of data values in a square bracket. Arrays can contain the same or different data types. Array values are referenced by their index. In JavaScript array index starts at zero. I.e., the first element of an array is found at index zero, the second element at index one, and the third element at index two, etc.
```js
let nums = [1, 2, 3]
nums[0] = 10
console.log(nums) // [10, 2, 3]
```
As you can see, an array, which is a non-primitive data type is mutable. Non-primitive data types cannot be compared by value. Even if two non-primitive data types have the same properties and values, they are not strictly equal.
```js
let nums = [1, 2, 3]
let numbers = [1, 2, 3]
console.log(nums == numbers) // false
let userOne = {
name:'Asabeneh',
role:'teaching',
country:'Finland'
}
let userTwo = {
name:'Asabeneh',
role:'teaching',
country:'Finland'
}
console.log(userOne == userTwo) // false
```
Rule of thumb, we do not compare non-primitive data types. Do not compare arrays, functions, or objects.
Non-primitive values are referred to as reference types, because they are being compared by reference instead of value. Two objects are only strictly equal if they refer to the same underlying object.
```js
let nums = [1, 2, 3]
let numbers = nums
console.log(nums == numbers) // true
let userOne = {
name:'Asabeneh',
role:'teaching',
country:'Finland'
}
let userTwo = userOne
console.log(userOne == userTwo) // true
```
If you have a hard time understanding the difference between primitive data types and non-primitive data types, you are not the only one. Calm down and just go to the next section and try to come back after some time. Now let us start the data types by number type.
## Numbers
Numbers are integers and decimal values which can do all the arithmetic operations.
Let's see some examples of Numbers.
### Declaring Number Data Types
```js
let age = 35
const gravity = 9.81 // we use const for non-changing values, gravitational constant in m/s2
let mass = 72 // mass in Kilogram
const PI = 3.14 // pi a geometrical constant
// More Examples
const boilingPoint = 100 // temperature in oC, boiling point of water which is a constant
const bodyTemp = 37 // oC average human body temperature, which is a constant
console.log(age, gravity, mass, PI, boilingPoint, bodyTemp)
```
### Math Object
In JavaScript the Math Object provides a lots of methods to work with numbers.
```js
const PI = Math.PI
console.log(PI) // 3.141592653589793
// Rounding to the closest number
// if above .5 up if less 0.5 down rounding
console.log(Math.round(PI)) // 3 to round values to the nearest number
console.log(Math.round(9.81)) // 10
console.log(Math.floor(PI)) // 3 rounding down
console.log(Math.ceil(PI)) // 4 rounding up
console.log(Math.min(-5, 3, 20, 4, 5, 10)) // -5, returns the minimum value
console.log(Math.max(-5, 3, 20, 4, 5, 10)) // 20, returns the maximum value
const randNum = Math.random() // creates random number between 0 to 0.999999
console.log(randNum)
// Let us create random number between 0 to 10
const num = Math.floor(Math.random () * 11) // creates random number between 0 and 10
console.log(num)
//Absolute value
console.log(Math.abs(-10)) // 10
//Square root
console.log(Math.sqrt(100)) // 10
console.log(Math.sqrt(2)) // 1.4142135623730951
// Power
console.log(Math.pow(3, 2)) // 9
console.log(Math.E) // 2.718
// Logarithm
// Returns the natural logarithm with base E of x, Math.log(x)
console.log(Math.log(2)) // 0.6931471805599453
console.log(Math.log(10)) // 2.302585092994046
// Returns the natural logarithm of 2 and 10 respectively
console.log(Math.LN2) // 0.6931471805599453
console.log(Math.LN10) // 2.302585092994046
// Trigonometry
Math.sin(0)
Math.sin(60)
Math.cos(0)
Math.cos(60)
```
#### Random Number Generator
The JavaScript Math Object has a random() method number generator which generates number from 0 to 0.999999999...
```js
let randomNum = Math.random() // generates 0 to 0.999...
```
Now, let us see how we can use random() method to generate a random number between 0 and 10:
```js
let randomNum = Math.random() // generates 0 to 0.999
let numBtnZeroAndTen = randomNum * 11
console.log(numBtnZeroAndTen) // this gives: min 0 and max 10.99
let randomNumRoundToFloor = Math.floor(numBtnZeroAndTen)
console.log(randomNumRoundToFloor) // this gives between 0 and 10
```
## Strings
Strings are texts, which are under **_single_** , **_double_**, **_back-tick_** quote. To declare a string, we need a variable name, assignment operator, a value under a single quote, double quote, or backtick quote.
Let's see some examples of strings:
```js
let space = ' ' // an empty space string
let firstName = 'Asabeneh'
let lastName = 'Yetayeh'
let country = 'Finland'
let city = 'Helsinki'
let language = 'JavaScript'
let job = 'teacher'
let quote = "The saying,'Seeing is Believing' is not correct in 2020."
let quotWithBackTick = `The saying,'Seeing is Believing' is not correct in 2020.`
```
### String Concatenation
Connecting two or more strings together is called concatenation.
Using the strings declared in the previous String section:
```js
let fullName = firstName + space + lastName; // concatenation, merging two string together.
console.log(fullName);
```
```sh
Asabeneh Yetayeh
```
We can concatenate strings in different ways.
#### Concatenating Using Addition Operator
Concatenating using the addition operator is an old way. This way of concatenating is tedious and error-prone. It is good to know how to concatenate this way, but I strongly suggest to use the ES6 template strings (explained later on).
```js
// Declaring different variables of different data types
let space = ' '
let firstName = 'Asabeneh'
let lastName = 'Yetayeh'
let country = 'Finland'
let city = 'Helsinki'
let language = 'JavaScript'
let job = 'teacher'
let age = 250
let fullName =firstName + space + lastName
let personInfoOne = fullName + '. I am ' + age + '. I live in ' + country; // ES5 string addition
console.log(personInfoOne)
```
```sh
Asabeneh Yetayeh. I am 250. I live in Finland
```
#### Long Literal Strings
A string could be a single character or paragraph or a page. If the string length is too big it does not fit in one line. We can use the backslash character (\\) at the end of each line to indicate that the string will continue on the next line.
**Example:**
```js
const paragraph = "My name is Asabeneh Yetayeh. I live in Finland, Helsinki.\
I am a teacher and I love teaching. I teach HTML, CSS, JavaScript, React, Redux, \
Node.js, Python, Data Analysis and D3.js for anyone who is interested to learn. \
In the end of 2019, I was thinking to expand my teaching and to reach \
to global audience and I started a Python challenge from November 20 - December 19.\
It was one of the most rewarding and inspiring experience.\
Now, we are in 2020. I am enjoying preparing the 30DaysOfJavaScript challenge and \
I hope you are enjoying too."
console.log(paragraph)
```
#### Escape Sequences in Strings
In JavaScript and other programming languages \ followed by some characters is an escape sequence. Let's see the most common escape characters:
- \n: new line
- \t: Tab, means 8 spaces
- \\\\: Back slash
- \\': Single quote (')
- \\": Double quote (")
```js
console.log('I hope everyone is enjoying the 30 Days Of JavaScript challenge.\nDo you ?') // line break
console.log('Days\tTopics\tExercises')
console.log('Day 1\t3\t5')
console.log('Day 2\t3\t5')
console.log('Day 3\t3\t5')
console.log('Day 4\t3\t5')
console.log('This is a backslash symbol (\\)') // To write a backslash
console.log('In every programming language it starts with \"Hello, World!\"')
console.log("In every programming language it starts with \'Hello, World!\'")
console.log('The saying \'Seeing is Believing\' isn\'t correct in 2020')
```
Output in console:
```sh
I hope everyone is enjoying the 30 Days Of JavaScript challenge.
Do you ?
Days Topics Exercises
Day 1 3 5
Day 2 3 5
Day 3 3 5
Day 4 3 5
This is a backslash symbol (\)
In every programming language it starts with "Hello, World!"
In every programming language it starts with 'Hello, World!'
The saying 'Seeing is Believing' isn't correct in 2020
```
#### Template Literals (Template Strings)
To create a template strings, we use two back-ticks. We can inject data as expressions inside a template string. To inject data, we enclose the expression with a curly bracket({}) preceded by a $ sign. See the syntax below.
```js
//Syntax
`String literal text`
`String literal text ${expression}`
```
**Example: 1**
```js
console.log(`The sum of 2 and 3 is 5`) // statically writing the data
let a = 2
let b = 3
console.log(`The sum of ${a} and ${b} is ${a + b}`) // injecting the data dynamically
```
**Example:2**
```js
let firstName = 'Asabeneh'
let lastName = 'Yetayeh'
let country = 'Finland'
let city = 'Helsinki'
let language = 'JavaScript'
let job = 'teacher'
let age = 250
let fullName = firstName + ' ' + lastName
let personInfoTwo = `I am ${fullName}. I am ${age}. I live in ${country}.` //ES6 - String interpolation method
let personInfoThree = `I am ${fullName}. I live in ${city}, ${country}. I am a ${job}. I teach ${language}.`
console.log(personInfoTwo)
console.log(personInfoThree)
```
```sh
I am Asabeneh Yetayeh. I am 250. I live in Finland.
I am Asabeneh Yetayeh. I live in Helsinki, Finland. I am a teacher. I teach JavaScript.
```
Using a string template or string interpolation method, we can add expressions, which could be a value, or some operations (comparison, arithmetic operations, ternary operation).
```js
let a = 2
let b = 3
console.log(`${a} is greater than ${b}: ${a > b}`)
```
```sh
2 is greater than 3: false
```
### String Methods
Everything in JavaScript is an object. A string is a primitive data type that means we can not modify it once it is created. The string object has many string methods. There are different string methods that can help us to work with strings.
1. *length*: The string *length* method returns the number of characters in a string included empty space.
**Example:**
```js
let js = 'JavaScript'
console.log(js.length) // 10
let firstName = 'Asabeneh'
console.log(firstName.length) // 8
```
2. *Accessing characters in a string*: We can access each character in a string using its index. In programming, counting starts from 0. The first index of the string is zero, and the last index is the length of the string minus one.
![Accessing sting by index](../images/string_indexes.png)
Let us access different characters in 'JavaScript' string.
```js
let string = 'JavaScript'
let firstLetter = string[0]
console.log(firstLetter) // J
let secondLetter = string[1] // a
let thirdLetter = string[2]
let lastLetter = string[9]
console.log(lastLetter) // t
let lastIndex = string.length - 1
console.log(lastIndex) // 9
console.log(string[lastIndex]) // t
```
3. *toUpperCase()*: this method changes the string to uppercase letters.
```js
let string = 'JavaScript'
console.log(string.toUpperCase()) // JAVASCRIPT
let firstName = 'Asabeneh'
console.log(firstName.toUpperCase()) // ASABENEH
let country = 'Finland'
console.log(country.toUpperCase()) // FINLAND
```
4. *toLowerCase()*: this method changes the string to lowercase letters.
```js
let string = 'JavasCript'
console.log(string.toLowerCase()) // javascript
let firstName = 'Asabeneh'
console.log(firstName.toLowerCase()) // asabeneh
let country = 'Finland'
console.log(country.toLowerCase()) // finland
```
5. *substr()*: It takes two arguments, the starting index and number of characters to slice.
```js
let string = 'JavaScript'
console.log(string.substr(4,6)) // Script
let country = 'Finland'
console.log(country.substr(3, 4)) // land
```
6. *substring()*: It takes two arguments, the starting index and the stopping index but it doesn't include the character at the stopping index.
```js
let string = 'JavaScript'
console.log(string.substring(0,4)) // Java
console.log(string.substring(4,10)) // Script
console.log(string.substring(4)) // Script
let country = 'Finland'
console.log(country.substring(0, 3)) // Fin
console.log(country.substring(3, 7)) // land
console.log(country.substring(3)) // land
```
7. *split()*: The split method splits a string at a specified place.
```js
let string = '30 Days Of JavaScript'
console.log(string.split()) // Changes to an array -> ["30 Days Of JavaScript"]
console.log(string.split(' ')) // Split to an array at space -> ["30", "Days", "Of", "JavaScript"]
let firstName = 'Asabeneh'
console.log(firstName.split()) // Change to an array - > ["Asabeneh"]
console.log(firstName.split('')) // Split to an array at each letter -> ["A", "s", "a", "b", "e", "n", "e", "h"]
let countries = 'Finland, Sweden, Norway, Denmark, and Iceland'
console.log(countries.split(',')) // split to any array at comma -> ["Finland", " Sweden", " Norway", " Denmark", " and Iceland"]
console.log(countries.split(', ')) //  ["Finland", "Sweden", "Norway", "Denmark", "and Iceland"]
```
8. *trim()*: Removes trailing space in the beginning or the end of a string.
```js
let string = ' 30 Days Of JavaScript '
console.log(string)
console.log(string.trim(' '))
let firstName = ' Asabeneh '
console.log(firstName)
console.log(firstName.trim()) // still removes spaces at the beginning and the end of the string
```
```sh
30 Days Of JavasCript
30 Days Of JavasCript
Asabeneh
Asabeneh
```
9. *includes()*: It takes a substring argument and it checks if substring argument exists in the string. *includes()* returns a boolean. If a substring exist in a string, it returns true, otherwise it returns false.
```js
let string = '30 Days Of JavaScript'
console.log(string.includes('Days')) // true
console.log(string.includes('days')) // false - it is case sensitive!
console.log(string.includes('Script')) // true
console.log(string.includes('script')) // false
console.log(string.includes('java')) // false
console.log(string.includes('Java')) // true
let country = 'Finland'
console.log(country.includes('fin')) // false
console.log(country.includes('Fin')) // true
console.log(country.includes('land')) // true
console.log(country.includes('Land')) // false
```
10. *replace()*: takes as a parameter the old substring and a new substring.
```js
string.replace(oldsubstring, newsubstring)
```
```js
let string = '30 Days Of JavaScript'
console.log(string.replace('JavaScript', 'Python')) // 30 Days Of Python
let country = 'Finland'
console.log(country.replace('Fin', 'Noman')) // Nomanland
```
11. *charAt()*: Takes index and it returns the value at that index
```js
string.charAt(index)
```
```js
let string = '30 Days Of JavaScript'
console.log(string.charAt(0)) // 3
let lastIndex = string.length - 1
console.log(string.charAt(lastIndex)) // t
```
12. *charCodeAt()*: Takes index and it returns char code (ASCII number) of the value at that index
```js
string.charCodeAt(index)
```
```js
let string = '30 Days Of JavaScript'
console.log(string.charCodeAt(3)) // D ASCII number is 68
let lastIndex = string.length - 1
console.log(string.charCodeAt(lastIndex)) // t ASCII is 116
```
13. *indexOf()*: Takes a substring and if the substring exists in a string it returns the first position of the substring if does not exist it returns -1
```js
string.indexOf(substring)
```
```js
let string = '30 Days Of JavaScript'
console.log(string.indexOf('D')) // 3
console.log(string.indexOf('Days')) // 3
console.log(string.indexOf('days')) // -1
console.log(string.indexOf('a')) // 4
console.log(string.indexOf('JavaScript')) // 11
console.log(string.indexOf('Script')) //15
console.log(string.indexOf('script')) // -1
```
14. *lastIndexOf()*: Takes a substring and if the substring exists in a string it returns the last position of the substring if it does not exist it returns -1
```js
//syntax
string.lastIndexOf(substring)
```
```js
let string = 'I love JavaScript. If you do not love JavaScript what else can you love.'
console.log(string.lastIndexOf('love')) // 67
console.log(string.lastIndexOf('you')) // 63
console.log(string.lastIndexOf('JavaScript')) // 38
```
15. *concat()*: it takes many substrings and joins them.
```js
string.concat(substring, substring, substring)
```
```js
let string = '30'
console.log(string.concat("Days", "Of", "JavaScript")) // 30DaysOfJavaScript
let country = 'Fin'
console.log(country.concat("land")) // Finland
```
16. *startsWith*: it takes a substring as an argument and it checks if the string starts with that specified substring. It returns a boolean(true or false).
```js
//syntax
string.startsWith(substring)
```
```js
let string = 'Love is the best to in this world'
console.log(string.startsWith('Love')) // true
console.log(string.startsWith('love')) // false
console.log(string.startsWith('world')) // false
let country = 'Finland'
console.log(country.startsWith('Fin')) // true
console.log(country.startsWith('fin')) // false
console.log(country.startsWith('land')) // false
```
17. *endsWith*: it takes a substring as an argument and it checks if the string ends with that specified substring. It returns a boolean(true or false).
```js
string.endsWith(substring)
```
```js
let string = 'Love is the most powerful feeling in the world'
console.log(string.endsWith('world')) // true
console.log(string.endsWith('love')) // false
console.log(string.endsWith('in the world')) // true
let country = 'Finland'
console.log(country.endsWith('land')) // true
console.log(country.endsWith('fin')) // false
console.log(country.endsWith('Fin')) // false
```
18. *search*: it takes a substring as an argument and it returns the index of the first match. The search value can be a string or a regular expression pattern.
```js
string.search(substring)
```
```js
let string = 'I love JavaScript. If you do not love JavaScript what else can you love.'
console.log(string.search('love')) // 2
console.log(string.search(/javascript/gi)) // 7
```
19. *match*: it takes a substring or regular expression pattern as an argument and it returns an array if there is match if not it returns null. Let us see how a regular expression pattern looks like. It starts with / sign and ends with / sign.
```js
let string = 'love'
let patternOne = /love/ // with out any flag
let patternTwo = /love/gi // g-means to search in the whole text, i - case insensitive
```
Match syntax
```js
// syntax
string.match(substring)
```
```js
let string = 'I love JavaScript. If you do not love JavaScript what else can you love.'
console.log(string.match('love'))
```
```sh
["love", index: 2, input: "I love JavaScript. If you do not love JavaScript what else can you love.", groups: undefined]
```
```js
let pattern = /love/gi
console.log(string.match(pattern)) // ["love", "love", "love"]
```
Let us extract numbers from text using a regular expression. This is not the regular expression section, do not panic! We will cover regular expressions later on.
```js
let txt = 'In 2019, I ran 30 Days of Python. Now, in 2020 I am super exited to start this challenge'
let regEx = /\d+/
// d with escape character means d not a normal d instead acts a digit
// + means one or more digit numbers,
// if there is g after that it means global, search everywhere.
console.log(txt.match(regEx)) // ["2", "0", "1", "9", "3", "0", "2", "0", "2", "0"]
console.log(txt.match(/\d+/g)) // ["2019", "30", "2020"]
```
20. *repeat()*: it takes a number as argument and it returns the repeated version of the string.
```js
string.repeat(n)
```
```js
let string = 'love'
console.log(string.repeat(10)) // lovelovelovelovelovelovelovelovelovelove
```
## Checking Data Types and Casting
### Checking Data Types
To check the data type of a certain variable we use the _typeof_ method.
**Example:**
```js
// Different javascript data types
// Let's declare different data types
let firstName = 'Asabeneh' // string
let lastName = 'Yetayeh' // string
let country = 'Finland' // string
let city = 'Helsinki' // string
let age = 250 // number, it is not my real age, do not worry about it
let job // undefined, because a value was not assigned
console.log(typeof 'Asabeneh') // string
console.log(typeof firstName) // string
console.log(typeof 10) // number
console.log(typeof 3.14) // number
console.log(typeof true) // boolean
console.log(typeof false) // boolean
console.log(typeof NaN) // number
console.log(typeof job) // undefined
console.log(typeof undefined) // undefined
console.log(typeof null) // object
```
### Changing Data Type (Casting)
- Casting: Converting one data type to another data type. We use _parseInt()_, _parseFloat()_, _Number()_, _+ sign_, _str()_
When we do arithmetic operations string numbers should be first converted to integer or float if not it returns an error.
#### String to Int
We can convert string number to a number. Any number inside a quote is a string number. An example of a string number: '10', '5', etc.
We can convert string to number using the following methods:
- parseInt()
- Number()
- Plus sign(+)
```js
let num = '10'
let numInt = parseInt(num)
console.log(numInt) // 10
```
```js
let num = '10'
let numInt = Number(num)
console.log(numInt) // 10
```
```js
let num = '10'
let numInt = +num
console.log(numInt) // 10
```
#### String to Float
We can convert string float number to a float number. Any float number inside a quote is a string float number. An example of a string float number: '9.81', '3.14', '1.44', etc.
We can convert string float to number using the following methods:
- parseFloat()
- Number()
- Plus sign(+)
```js
let num = '9.81'
let numFloat = parseFloat(num)
console.log(numFloat) // 9.81
```
```js
let num = '9.81'
let numFloat = Number(num)
console.log(numFloat) // 9.81
```
```js
let num = '9.81'
let numFloat = +num
console.log(numFloat) // 9.81
```
#### Float to Int
We can convert float numbers to integers.
We use the following method to convert float to int:
- parseInt()
```js
let num = 9.81
let numInt = parseInt(num)
console.log(numInt) // 9
```
🌕 You are awesome. You have just completed day 2 challenges and you are two steps ahead on your way to greatness. Now do some exercises for your brain and for your muscle.
## 💻 Day 2: Exercises
### Exercise: Level 1
1. Declare a variable named challenge and assign it to an initial value **'30 Days Of JavaScript'**.
2. Print the string on the browser console using __console.log()__
3. Print the __length__ of the string on the browser console using _console.log()_
4. Change all the string characters to capital letters using __toUpperCase()__ method
5. Change all the string characters to lowercase letters using __toLowerCase()__ method
6. Cut (slice) out the first word of the string using __substr()__ or __substring()__ method
7. Slice out the phrase *Days Of JavaScript* from *30 Days Of JavaScript*.
8. Check if the string contains a word __Script__ using __includes()__ method
9. Split the __string__ into an __array__ using __split()__ method
10. Split the string 30 Days Of JavaScript at the space using __split()__ method
11. 'Facebook, Google, Microsoft, Apple, IBM, Oracle, Amazon' __split__ the string at the comma and change it to an array.
12. Change 30 Days Of JavaScript to 30 Days Of Python using __replace()__ method.
13. What is character at index 15 in '30 Days Of JavaScript' string? Use __charAt()__ method.
14. What is the character code of J in '30 Days Of JavaScript' string using __charCodeAt()__
15. Use __indexOf__ to determine the position of the first occurrence of __a__ in 30 Days Of JavaScript
16. Use __lastIndexOf__ to determine the position of the last occurrence of __a__ in 30 Days Of JavaScript.
17. Use __indexOf__ to find the position of the first occurrence of the word __because__ in the following sentence:__'You cannot end a sentence with because because because is a conjunction'__
18. Use __lastIndexOf__ to find the position of the last occurrence of the word __because__ in the following sentence:__'You cannot end a sentence with because because because is a conjunction'__
19. Use __search__ to find the position of the first occurrence of the word __because__ in the following sentence:__'You cannot end a sentence with because because because is a conjunction'__
20. Use __trim()__ to remove any trailing whitespace at the beginning and the end of a string.E.g ' 30 Days Of JavaScript '.
21. Use __startsWith()__ method with the string *30 Days Of JavaScript* and make the result true
22. Use __endsWith()__ method with the string *30 Days Of JavaScript* and make the result true
23. Use __match()__ method to find all the __a__’s in 30 Days Of JavaScript
24. Use __concat()__ and merge '30 Days of' and 'JavaScript' to a single string, '30 Days Of JavaScript'
25. Use __repeat()__ method to print 30 Days Of JavaScript 2 times
### Exercise: Level 2
1. Using console.log() print out the following statement:
```sh
The quote 'There is no exercise better for the heart than reaching down and lifting people up.' by John Holmes teaches us to help one another.
```
2. Using console.log() print out the following quote by Mother Teresa:
```sh
"Love is not patronizing and charity isn't about pity, it is about love. Charity and love are the same -- with charity you give love, so don't just give money but reach out your hand instead."
```
3. Check if typeof '10' is exactly equal to 10. If not make it exactly equal.
4. Check if parseFloat('9.8') is equal to 10 if not make it exactly equal with 10.
5. Check if 'on' is found in both python and jargon
6. _I hope this course is not full of jargon_. Check if _jargon_ is in the sentence.
7. Generate a random number between 0 and 100 inclusively.
8. Generate a random number between 50 and 100 inclusively.
9. Generate a random number between 0 and 255 inclusively.
10. Access the 'JavaScript' string characters using a random number.
11. Use console.log() and escape characters to print the following pattern.
```js
1 1 1 1 1
2 1 2 4 8
3 1 3 9 27
4 1 4 16 64
5 1 5 25 125
```
12. Use __substr__ to slice out the phrase __because because because__ from the following sentence:__'You cannot end a sentence with because because because is a conjunction'__
### Exercises: Level 3
1. 'Love is the best thing in this world. Some found their love and some are still looking for their love.' Count the number of word __love__ in this sentence.
2. Use __match()__ to count the number of all __because__ in the following sentence:__'You cannot end a sentence with because because because is a conjunction'__
3. Clean the following text and find the most frequent word (hint, use replace and regular expressions).
```js
const sentence = '%I $am@% a %tea@cher%, &and& I lo%#ve %te@a@ching%;. The@re $is no@th@ing; &as& mo@re rewarding as educa@ting &and& @emp%o@weri@ng peo@ple. ;I found tea@ching m%o@re interesting tha@n any ot#her %jo@bs. %Do@es thi%s mo@tiv#ate yo@u to be a tea@cher!? %Th#is 30#Days&OfJavaScript &is al@so $the $resu@lt of &love& of tea&ching'
```
4. Calculate the total annual income of the person by extracting the numbers from the following text. 'He earns 5000 euro from salary per month, 10000 euro annual bonus, 15000 euro online courses per month.'
🎉 CONGRATULATIONS ! 🎉
[<< Day 1](../readMe.md) | [Day 3 >>](../03_Day_Booleans_operators_date/03_booleans_operators_date.md)

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<!DOCTYPE html>
<html lang="en">
<head>
<title>30DaysOfJavaScript</title>
</head>
<body>
<h1>30DaysOfJavaScript:02 Day</h1>
<h2>Data types</h2>
<!-- import your scripts here -->
<script src="./main.js"></script>
</body>
</html>

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// this is your main.js script

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const PI = Math.PI
console.log(PI) // 3.141592653589793
console.log(Math.round(PI)) // 3; to round values to the nearest number
console.log(Math.round(9.81)) // 10
console.log(Math.floor(PI)) // 3; rounding down
console.log(Math.ceil(PI)) // 4; rounding up
console.log(Math.min(-5, 3, 20, 4, 5, 10)) // -5, returns the minimum value
console.log(Math.max(-5, 3, 20, 4, 5, 10)) // 20, returns the maximum value
const randNum = Math.random() // creates random number between 0 to 0.999999
console.log(randNum)
// Let create random number between 0 to 10
const num = Math.floor(Math.random() * 11) // creates random number between 0 and 10
console.log(num)
//Absolute value
console.log(Math.abs(-10)) //10
//Square root
console.log(Math.sqrt(100)) // 10
console.log(Math.sqrt(2)) //1.4142135623730951
// Power
console.log(Math.pow(3, 2)) // 9
console.log(Math.E) // 2.718
// Logarithm
//Returns the natural logarithm of base E of x, Math.log(x)
console.log(Math.log(2)) // 0.6931471805599453
console.log(Math.log(10)) // 2.302585092994046
// Trigonometry
console.log(Math.sin(0))
console.log(Math.sin(60))
console.log(Math.cos(0))
console.log(Math.cos(60))

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let nums = [1, 2, 3]
nums[0] = 10
console.log(nums) // [10, 2, 3]
let nums = [1, 2, 3]
let numbers = [1, 2, 3]
console.log(nums == numbers) // false
let userOne = {
name: 'Asabeneh',
role: 'teaching',
country: 'Finland'
}
let userTwo = {
name: 'Asabeneh',
role: 'teaching',
country: 'Finland'
}
console.log(userOne == userTwo) // false
let numbers = nums
console.log(nums == numbers) // true
let userOne = {
name:'Asabeneh',
role:'teaching',
country:'Finland'
}
let userTwo = userOne
console.log(userOne == userTwo) // true

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let age = 35
const gravity = 9.81 //we use const for non-changing values, gravitational constant in m/s2
let mass = 72 // mass in Kilogram
const PI = 3.14 // pi a geometrical constant
//More Examples
const boilingPoint = 100 // temperature in oC, boiling point of water which is a constant
const bodyTemp = 37 // oC average human body temperature, which is a constant
console.log(age, gravity, mass, PI, boilingPoint, bodyTemp)

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let word = 'JavaScript'
// we dont' modify string
// we don't do like this, word[0] = 'Y'
let numOne = 3
let numTwo = 3
console.log(numOne == numTwo) // true
let js = 'JavaScript'
let py = 'Python'
console.log(js == py) //false
let lightOn = true
let lightOff = false
console.log(lightOn == lightOff) // false

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// Declaring different variables of different data types
let space = ' '
let firstName = 'Asabeneh'
let lastName = 'Yetayeh'
let country = 'Finland'
let city = 'Helsinki'
let language = 'JavaScript'
let job = 'teacher'
// Concatenating using addition operator
let fullName = firstName + space + lastName // concatenation, merging two string together.
console.log(fullName)
let personInfoOne = fullName + '. I am ' + age + '. I live in ' + country // ES5
console.log(personInfoOne)
// Concatenation: Template Literals(Template Strings)
let personInfoTwo = `I am ${fullName}. I am ${age}. I live in ${country}.` //ES6 - String interpolation method
let personInfoThree = `I am ${fullName}. I live in ${city}, ${country}. I am a ${job}. I teach ${language}.`
console.log(personInfoTwo)
console.log(personInfoThree)

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let space = ' ' // an empty space string
let firstName = 'Asabeneh'
let lastName = 'Yetayeh'
let country = 'Finland'
let city = 'Helsinki'
let language = 'JavaScript'
let job = 'teacher'

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// Let us access the first character in 'JavaScript' string.
let string = 'JavaScript'
let firstLetter = string[0]
console.log(firstLetter) // J
let secondLetter = string[1] // a
let thirdLetter = string[2]
let lastLetter = string[9]
console.log(lastLetter) // t
let lastIndex = string.length - 1
console.log(lastIndex) // 9
console.log(string[lastIndex]) // t

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// charAt(): Takes index and it returns the value at that index
string.charAt(index)
let string = '30 Days Of JavaScript'
console.log(string.charAt(0)) // 3
let lastIndex = string.length - 1
console.log(string.charAt(lastIndex)) // t

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// charCodeAt(): Takes index and it returns char code(ASCII number) of the value at that index
string.charCodeAt(index)
let string = '30 Days Of JavaScript'
console.log(string.charCodeAt(3)) // D ASCII number is 51
let lastIndex = string.length - 1
console.log(string.charCodeAt(lastIndex)) // t ASCII is 116

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// concat(): it takes many substrings and creates concatenation.
// string.concat(substring, substring, substring)
let string = '30'
console.log(string.concat("Days", "Of", "JavaScript")) // 30DaysOfJavaScript
let country = 'Fin'
console.log(country.concat("land")) // Finland

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// endsWith: it takes a substring as an argument and it checks if the string starts with that specified substring. It returns a boolean(true or false).
// string.endsWith(substring)
let string = 'Love is the best to in this world'
console.log(string.endsWith('world')) // true
console.log(string.endsWith('love')) // false
console.log(string.endsWith('in this world')) // true
let country = 'Finland'
console.log(country.endsWith('land')) // true
console.log(country.endsWith('fin')) // false
console.log(country.endsWith('Fin')) // false

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// includes(): It takes a substring argument and it check if substring argument exists in the string. includes() returns a boolean. It checks if a substring exist in a string and it returns true if it exists and false if it doesn't exist.
let string = '30 Days Of JavaScript'
console.log(string.includes('Days')) // true
console.log(string.includes('days')) // false
console.log(string.includes('Script')) // true
console.log(string.includes('script')) // false
console.log(string.includes('java')) // false
console.log(string.includes('Java')) // true
let country = 'Finland'
console.log(country.includes('fin')) // false
console.log(country.includes('Fin')) // true
console.log(country.includes('land')) // true
console.log(country.includes('Land')) // false

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// indexOf(): Takes takes a substring and if the substring exists in a string it returns the first position of the substring if does not exist it returns -1
string.indexOf(substring)
let string = '30 Days Of JavaScript'
console.log(string.indexOf('D')) // 3
console.log(string.indexOf('Days')) // 3
console.log(string.indexOf('days')) // -1
console.log(string.indexOf('a')) // 4
console.log(string.indexOf('JavaScript')) // 11
console.log(string.indexOf('Script')) //15
console.log(string.indexOf('script')) // -1

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// lastIndexOf(): Takes takes a substring and if the substring exists in a string it returns the last position of the substring if it does not exist it returns -1
let string = 'I love JavaScript. If you do not love JavaScript what else can you love.'
console.log(string.lastIndexOf('love')) // 67
console.log(string.lastIndexOf('you')) // 63
console.log(string.lastIndexOf('JavaScript')) // 38

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// length: The string length method returns the number of characters in a string included empty space. Example:
let js = 'JavaScript'
console.log(js.length) // 10
let firstName = 'Asabeneh'
console.log(firstName.length) // 8

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// match: it takes a substring or regular expression pattern as an argument and it returns an array if there is match if not it returns null. Let us see how a regular expression pattern looks like. It starts with / sign and ends with / sign.
let string = 'love'
let patternOne = /love/ // with out any flag
let patternTwo = /love/gi // g-means to search in the whole text, i - case insensitive
string.match(substring)
let string = 'I love JavaScript. If you do not love JavaScript what else can you love.'
console.log(string.match('love')) //
/*
output
["love", index: 2, input: "I love JavaScript. If you do not love JavaScript what else can you love.", groups: undefined]
*/
let pattern = /love/gi
console.log(string.match(pattern)) // ["love", "love", "love"]
// Let us extract numbers from text using regular expression. This is not regular expression section, no panic.
let txt = 'In 2019, I run 30 Days of Python. Now, in 2020 I super exited to start this challenge'
let regEx = /\d/g // d with escape character means d not a normal d instead acts a digit
// + means one or more digit numbers,
// if there is g after that it means global, search everywhere.
console.log(txt.match(regEx)) // ["2", "0", "1", "9", "3", "0", "2", "0", "2", "0"]
console.log(txt.match(/\d+/g)) // ["2019", "30", "2020"]

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// repeat(): it takes a number argument and it returned the repeated version of the string.
// string.repeat(n)
let string = 'love'
console.log(string.repeat(10)) // lovelovelovelovelovelovelovelovelovelove

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// replace(): takes to parameter the old substring and new substring.
// string.replace(oldsubstring, newsubstring)
let string = '30 Days Of JavaScript'
console.log(string.replace('JavaScript', 'Python')) // 30 Days Of Python
let country = 'Finland'
console.log(country.replace('Fin', 'Noman')) // Nomanland

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// search: it takes a substring as an argument and it returns the index of the first match.
// string.search(substring)
let string = 'I love JavaScript. If you do not love JavaScript what else can you love.'
console.log(string.search('love')) // 2

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// split(): The split method splits a string at a specified place.
let string = '30 Days Of JavaScript'
console.log(string.split()) // ["30 Days Of JavaScript"]
console.log(string.split(' ')) // ["30", "Days", "Of", "JavaScript"]
let firstName = 'Asabeneh'
console.log(firstName.split()) // ["Asabeneh"]
console.log(firstName.split('')) // ["A", "s", "a", "b", "e", "n", "e", "h"]
let countries = 'Finland, Sweden, Norway, Denmark, and Iceland'
console.log(countries.split(',')) // ["Finland", " Sweden", " Norway", " Denmark", " and Iceland"]
console.log(countries.split(', ')) // ["Finland", "Sweden", "Norway", "Denmark", "and Iceland"]

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// startsWith: it takes a substring as an argument and it checks if the string starts with that specified substring. It returns a boolean(true or false).
// string.startsWith(substring)
let string = 'Love is the best to in this world'
console.log(string.startsWith('Love')) // true
console.log(string.startsWith('love')) // false
console.log(string.startsWith('world')) // false
let country = 'Finland'
console.log(country.startsWith('Fin')) // true
console.log(country.startsWith('fin')) // false
console.log(country.startsWith('land')) // false

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//substr(): It takes two arguments,the starting index and number of characters to slice.
let string = 'JavaScript'
console.log(string.substr(4,6)) // Script
let country = 'Finland'
console.log(country.substr(3, 4)) // land

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// substring(): It takes two arguments,the starting index and the stopping index but it doesn't include the stopping index.
let string = 'JavaScript'
console.log(string.substring(0,4)) // Java
console.log(string.substring(4,10)) // Script
console.log(string.substring(4)) // Script
let country = 'Finland'
console.log(country.substring(0, 3)) // Fin
console.log(country.substring(3, 7)) // land
console.log(country.substring(3)) // land

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// toLowerCase(): this method changes the string to lowercase letters.
let string = 'JavasCript'
console.log(string.toLowerCase()) // javascript
let firstName = 'Asabeneh'
console.log(firstName.toLowerCase()) // asabeneh
let country = 'Finland'
console.log(country.toLowerCase()) // finland

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// toUpperCase(): this method changes the string to uppercase letters.
let string = 'JavaScript'
console.log(string.toUpperCase()) // JAVASCRIPT
let firstName = 'Asabeneh'
console.log(firstName.toUpperCase()) // ASABENEH
let country = 'Finland'
console.log(country.toUpperCase()) // FINLAND

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//trim(): Removes trailing space in the beginning or the end of a string.
let string = ' 30 Days Of JavaScript '
console.log(string) //
console.log(string.trim(' ')) //
let firstName = ' Asabeneh '
console.log(firstName)
console.log(firstName.trim()) //

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## Introdução
**Parabéns** Em decidir de participar desafio dos 30 dias de JavaScript. Neste desafio você aprenderá tudo que precisa para ser um programador JavaScript, e em general, todo o conceito de programação. No fim do desafio voce estará adquirindo o Certificado de conclusão do desafio 30DaysOfJavaScript. Em caso de precisar de ajuda ou se preferir ajudar outros você pode entrar no [Grupo Telegram](https://t.me/ThirtyDaysOfJavaScript).
**Parabéns** Em decidir de participar do desafio 30DaysOfJavaScript. Neste desafio você aprenderá tudo que precisa para ser um programador JavaScript, e em general, todo o conceito de programação. No fim do desafio voce estará adquirindo o Certificado de conclusão do desafio 30DaysOfJavaScript. Em caso de precisar de ajuda ou se preferir ajudar outros você pode entrar no [Grupo Telegram](https://t.me/ThirtyDaysOfJavaScript).
**30DaysOfJavaScript** desafio é um guia tanto para iniciantes e Avançados JavaScript Desenvolvedores, Bem vindo ao JavaScript. JavaScript é a linguagem da internet. Eu me divirto em usar e ensinar JavaScript e eu acredito que voce fará tambem.
@ -508,12 +508,12 @@ console.log(firstName) // undefined, because it is not assigned to a value yet
Null em JavaScript significa um valor vazio.
```js
let emptyValue = null
let valorVazio = null
```
## Verificando Tipos de Dados
Para verificar o tipo de dado de uma determinada variavel, no usamos o operador **typeof**. Veja o seguinte exemplo.
Para verificar o tipo de dado de uma determinada variável, nós usamos o operador **typeof**. Veja o seguinte exemplo.
```js
console.log(typeof 'Asabeneh') // string
@ -523,45 +523,45 @@ console.log(typeof null) // object type
console.log(typeof undefined) // undefined
```
## Comentários de novo
## Comentários novamente
Remember that commenting in JavaScript is similar to other programming languages. Comments are important in making your code more readable.
There are two ways of commenting:
Lembre que comentando no JavaScript é similar à outras linguagens de programação. Comentários são importantes em fazer mais fácil a leitura do seu código.
Existe dois modos de comentar:
- _Single line commenting_
- _Multiline commenting_
- _Comentando em linha única_
- _Comentando em várias linhas_
```js
// commenting the code itself with a single comment
// let firstName = 'Asabeneh'; single line comment
// let lastName = 'Yetayeh'; single line comment
// Comentando o código com um único comentário
// let firstName = 'Asabeneh'; Comentando em linha única_
// let lastName = 'Yetayeh'; Comentando em linha única_
```
Multiline commenting:
Comentando em várias linhas:
```js
/*
let location = 'Helsinki';
let age = 100;
let isMarried = true;
This is a Multiple line comment
Isto é um comentário em linha única
*/
```
## Variables
## Variáveis
Variables are _containers_ of data. Variables are used to _store_ data in a memory location. When a variable is declared, a memory location is reserved. When a variable is assigned to a value (data), the memory space will be filled with that data. To declare a variable, we use _var_, _let_, or _const_ keywords.
Variáveis são _containers_ de dados. Variáveis são usadas para _armazenar_ dados na memória alocada. Quando variáveis são declaradas, uma memória alocada é reservada. Quando uma variável é atribuída para um valor (dados), espaço na memória irá ser preenchido com aqueles dados. Para declarar uma variável, nós usamos as palavras-chaves _var_, _let_, ou _const_.
For a variable that changes at a different time, we use _let_. If the data does not change at all, we use _const_. For example, PI, country name, gravity do not change, and we can use _const_. We will not use var in this challenge and I don't recommend you to use it. It is error prone way of declaring variable it has lots of leak. We will talk more about var, let, and const in detail in other sections (scope). For now, the above explanation is enough.
Para uma variável que muda com o tempo, nós usamos _let_. Se os dados não vão mudar, nós usamos _const_. Por exemplo, PI, nome de país, gravidade não muda, e nós podemos usar _const_. Nós não vamos usar var neste desafio e eu nao recomendo usa-lo. Nós vamos falar mais sobre var, let, e const em detalhes em outras sessões (scope). Por enquanto, a explicação acima é suficiente.
A valid JavaScript variable name must follow the following rules:
Um nome de variável em JavaScript apenas segue a seguinte regra:
- A JavaScript variable name should not begin with a number.
- A JavaScript variable name does not allow special characters except dollar sign and underscore.
- A JavaScript variable name follows a camelCase convention.
- A JavaScript variable name should not have space between words.
- Um nome de variável não deverá começar com um número.
- Um nome de variável não pode permitir caracteres especiais exceto o sinal do dólar e underscore.
- Um nome de variável segue a convenção camelCase.
- Um nomede variável não deve ter espaços entre as palavras.
The following are examples of valid JavaScript variables.
Os seguintes exemplos são de variáveis válidas em JavaScript.
```js
firstName
@ -585,9 +585,9 @@ year2020
year_2020
```
The first and second variables on the list follows the camelCase convention of declaring in JavaScript. In this material, we will use camelCase variables(camelWithOneHump). We use CamelCase(CamelWithTwoHump) to declare classes, we will discuss about classes and objects in other section.
A primeira e a segunda variável na lista segue a convenção camelCase de declaração no JavaScript. Neste material, nós vamos usar variáveis em camelCase (camelWithOneHump). Nós usamos CamelCase (CamelWithTwoHump) para declarar classes, nós vamos discutir sobre classes e objetos em outras sessões.
Example of invalid variables:
Exemplo de variáveis invalidas:
```js
first-name
@ -595,24 +595,24 @@ Example of invalid variables:
num_#_1
```
Let us declare variables with different data types. To declare a variable, we need to use _let_ or _const_ keyword before the variable name. Following the variable name, we write an equal sign (assignment operator), and a value(assigned data).
Vamos declarar variáveis com diferentes tipos de dados. Para declarar uma variável, nós precisamos usar as palavras-chaves _let_ ou _const_ antes de um nome de variável. Após o nome da variável, nós escrevemos um sinal de igual (operador de atribuição), e um valor (dados atribuidos).
```js
// Syntax
// Sintaxe
let nameOfVariable = value
```
The nameOfVriable is the name that stores different data of value. See below for detail examples.
O nomeDaVariavel é o nome que armazena diferente tipos de dados. Veja abaixo exemplos para mais detalhes.
**Examples of declared variables**
**Exemplos de variáveis declaradas**
```js
// Declaring different variables of different data types
let firstName = 'Asabeneh' // first name of a person
let lastName = 'Yetayeh' // last name of a person
let country = 'Finland' // country
let city = 'Helsinki' // capital city
let age = 100 // age in years
// Declarando diferentes variáveis de diferentes tipos de dados
let firstName = 'Asabeneh' // primeiro nome de uma pessoa
let lastName = 'Yetayeh' // ultimo nome de uma pessoa
let country = 'Finland' // país
let city = 'Helsinki' // capital da cidade
let age = 100 // Idade
let isMarried = true
console.log(firstName, lastName, country, city, age, isMarried)
@ -623,11 +623,11 @@ Asabeneh Yetayeh Finland Helsinki 100 true
```
```js
// Declaring variables with number values
let age = 100 // age in years
const gravity = 9.81 // earth gravity in m/s2
const boilingPoint = 100 // water boiling point, temperature in °C
const PI = 3.14 // geometrical constant
// Declarando variáveis com o valor numérico
let age = 100 // idade
const gravity = 9.81 // gravidade na terra em m/s2
const boilingPoint = 100 // ponto de ebulição da água, temperatura em °C
const PI = 3.14 // constante geométrica
console.log(gravity, boilingPoint, PI)
```
@ -636,7 +636,7 @@ console.log(gravity, boilingPoint, PI)
```
```js
// Variables can also be declaring in one line separated by comma, however I recommend to use a seperate line to make code more readble
// Variáveis tambem podem ser declaradas em uma linha separadas por uma vírgula, entretanto eu recomento usar a separação por linha para facilitar a leitura do código
let name = 'Asabeneh', job = 'teacher', live = 'Finland'
console.log(name, job, live)
```
@ -645,32 +645,30 @@ console.log(name, job, live)
Asabeneh teacher Finland
```
When you run _index.html_ file in the 01-Day folder you should get this:
Quando você executa o arquivo _index.html_ na pasta dia-1 você deve conseguir isto:
![Day one](/images/day_1.png)
🌕 You are amazing! You have just completed day 1 challenge and you are on your way to greatness. Now do some exercises for your brain and muscle.
🌕 Você é incrivel! Você acaba de completar o desafio do dia 1 e você está no seu caminho para a grandeza. Agora faça alguns exercícios para seu cérebro e músculos.
# 💻 Day 1: Exercises
# 💻 Dia 1: Exercícios
1. Write a single line comment which says, _comments can make code readable_
2. Write another single comment which says, _Welcome to 30DaysOfJavaScript_
3. Write a multiline comment which says, _comments can make code readable, easy to reuse_
_and informative_
4. Create a variable.js file and declare variables and assign string, boolean, undefined and null data types
5. Create datatypes.js file and use the JavaScript **_typeof_** operator to check different data types. Check the data type of each variable
6. Declare four variables without assigning values
7. Declare four variables with assigned values
8. Declare variables to store your first name, last name, marital status, country and age in multiple lines
9. Declare variables to store your first name, last name, marital status, country and age in a single line
10. Declare two variables _myAge_ and _yourAge_ and assign them initial values and log to the browser console.
1. Escreva um comentário de linha única que diga, _comentários faz seu código ser fácil de ler_
2. Escreva outro comentário de linha única que diga, _Welcome to 30DaysOfJavaScript_
3. Escreva um comentário de várias linhas que diga, _comentários faz seu código ser fácil de ler, fácil de reusar_ _e informátivo_
4. Crie um arquivo variavel.js e declare variáveis e atribua uma string, boolean, undefined e null
5. Crie um arquivo tiposdedados.js e use o JavaScript **_typeof_** operador para verificar diferentes tipos de dados. Verifique o tipo de dado de cada variável
6. Declare quatro variáveis sem atribuir valores
7. Declare quatro variáveis e atribuir valores
8. Declare variáveis para armazenar seu primeiro nome, ultimo nome, estado civil, país e idade em multiplas linhas
9. Declare variáveis para armazenar seu primeiro nome, ultimo nome, estado civil, país e idade em uma única linha
10. Declare duas variáveis _minhaIdade_ e _suaIdade_ e atribua valores iniciais e mostre no console do navegador.
```sh
I am 25 years old.
You are 30 years old.
```
🎉 CONGRATULATIONS ! 🎉
🎉 PARABÉNS ! 🎉
[Dia 2 >>](./02_Day_Data_types/02_day_data_types.md)

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