- [Array containing all of the match](#array-containing-all-of-the-match)
- [Replacing a substring](#replacing-a-substring)
- [Square Bracket](#square-bracket)
- [Escape character(\\) in RegEx](#escape-character-in-regex)
- [Escape character(\\) in RegExp](#escape-character-in-regex)
- [One or more times(+)](#one-or-more-times)
- [Period(.)](#period)
- [Zero or more times(*)](#zero-or-more-times)
- [Zero or one times(?)](#zero-or-one-times)
- [Quantifier in RegEx](#quantifier-in-regex)
- [Quantifier in RegExp](#quantifier-in-regex)
- [Cart ^](#cart)
- [Exact match](#exact-match)
- [💻 Exercises](#%f0%9f%92%bb-exercises)
@ -46,11 +46,11 @@
## Regular Expressions
A regular expression or RegEx is a small programming language that helps to find pattern in data. A RegEx can be used to check if some pattern exists in a different data types. To use RegEx in JavaScript either we use RegEx constructor or we can declare a RegEx pattern using two forward slashes followed by a flag. We can create a pattern in two ways.
A regular expression or RegExp is a small programming language that helps to find pattern in data. A RegExp can be used to check if some pattern exists in a different data types. To use RegExp in JavaScript either we use RegExp constructor or we can declare a RegExp pattern using two forward slashes followed by a flag. We can create a pattern in two ways.
To declare a string we use a single quote, double quote a backtick to declare a regular expression we use two forward slashes and an optional flag. The flag could be g, i, m, s, u or y.
### RegEx parameters
### RegExp parameters
A regular expression takes two parameters. One required search pattern and an optional flag.
@ -66,14 +66,14 @@ Flags are optional parameters in a regular expression which determine the type o
- i: case insensitive flag(it searches for both lowercase and uppercase)
- m: multiline
### Creating a pattern with RegEx Constructor
### Creating a pattern with RegExp Constructor
Declaring regular expression without global flag and case insensitive flag.
```js
// without flag
let pattern = 'love'
let regEx = new RegEx(pattern)
let regEx = new RegExp(pattern)
```
Declaring regular expression with global flag and case insensitive flag.
@ -81,16 +81,16 @@ Declaring regular expression with global flag and case insensitive flag.
```js
let pattern = 'love'
let flag = 'gi'
let regEx = new RegEx(pattern, flag)
let regEx = new RegExp(pattern, flag)
```
Declaring a regex pattern using RegEx object. Writing the pattern and the flag inside the RegEx constructor
Declaring a regex pattern using RegExp object. Writing the pattern and the flag inside the RegExp constructor
```js
let regEx = new RegEx('love','gi')
let regEx = new RegExp('love','gi')
```
### Creating a pattern without RegEx Constructor
### Creating a pattern without RegExp Constructor
Declaring regular expression with global flag and case insensitive flag.
@ -98,15 +98,15 @@ Declaring regular expression with global flag and case insensitive flag.
let regEx= /love/gi
```
The above regular expression is the same as the one which we created with RegEx constructor
The above regular expression is the same as the one which we created with RegExp constructor
```js
let regEx= new RegEx('love','gi')
let regEx= new RegExp('love','gi')
```
### RegExp Object Methods
### RegExpp Object Methods
Let see some of RegEx methods
Let see some of RegExp methods
#### Testing for a match
@ -297,7 +297,7 @@ console.log(matches)
Using the square bracket and or operator , we manage to extract Apple, apple, Banana and banana.
### Escape character(\\) in RegEx
### Escape character(\\) in RegExp
```js
const pattern = /\d/g // d is a special character which means digits
We can specify the length of the substring we look for in a text, using a curly bracket. Lets imagine, we are interested in substring that their length are 4 characters
Venkat Prasadh
4 years ago