map filter reduce

solutions/day-01/functional.js

@@ -0,0 +1,39 @@
+countries.forEach(function (country, i, arr) {
+    console.log(i, country.toUpperCase())
+})
+
+countries.forEach((country, i) => console.log(i, country.toUpperCase()))
+
+const newCountries = []
+
+countries.forEach((country) => newCountries.push(country))
+
+console.log(newCountries)
+
+let sumForeach = 0
+numbers.forEach((n) => (sumForeach += n))
+console.log(sumForeach)
+
+// map is very handy to modify an array and returns with an array
+const newerCountries = countries.map((country) => country.toUpperCase())
+console.log(newerCountries)
+
+// lets return the length of word of each country as an array
+const countriesLength = countries.map((country) => country.length)
+console.log(countriesLength)
+
+// use filter with map to filter the iteration and select for specific things, such as 
+// countries that end with 'land'
+
+const countriesWithLand = countries.filter((country) => country.includes('land'))
+console.log(countriesWithLand)
+
+// or... filtering out countries that do not include 'land'
+const countriesWithoutLand = countries.filter((country) => !country.includes('land'))
+console.log(countriesWithoutLand)
+
+const newNumbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+const evens = newNumbers.filter((n) => n % 2 === 0)
+const odds = newNumbers.filter((n) => n % 2 !== 0)
+console.log(odds)
+console.log(evens)