JAvaScriptにおける配列拡張
2082 ワード
let Like = {
'0':'a',
'1':'b',
'2':'c'
}
var arr = Array.from(Like)
console.log(arr)
let Like = [1,2,3]
var arr2 = Array.from(Like,(x) =>x * x)
console.log(arr2)
var TheNumerical = 26
var TheNumerical1 = Array.of(TheNumerical)
console.log(TheNumerical1)
var arr2 = [1,2,3,4,5,6,7,8]
var arr3 = arr2.copyWithin(0,3)
console.log(arr3)
// [4,5,3,4,5,6,7,8]
var arr4 = [1,2,3,4,5]
var arr5 = arr4.copyWithin(0,3,4)
console.log(arr5)
//[4,2,3,4,5]
var arr6 = [1,5,8,-9,15]
var arr7 = arr6.find((x) > 8 )
console.log(arr7)
var arr8 = [1,7,9,15]
var arr9 = arr8.findIndex(function(value,index,arr){
return value > 9
})
console.log(arr9)
// 3
var arr10 = [1,5,7,8,9,]
var arr11 = arr10.includes(5)
var arr12 = arr10.includes(4)
console.log(arr11)//true
console.log(arr12)//false
var arr13 = [2,3,4,5]
var arr14 = [for(i of arr13) i *2]
console.log(arr14)//4,6,8,10
var arr15 = [2,3,4,5]
var arr16 = arr15.map(() => i * 2)
console.log(arr16)//4,6,8,10
関数の拡張
function arr(x,y='b'){
console.log(x,y)
}
arr(a)
//a,b