本篇文章給大家總結(jié)了一些javascript遍歷數(shù)組的幾種方法。有一定的參考價值，有需要的朋友可以參考一下，希望對大家有所幫助。
有幾種方法可以遍歷數(shù)組，下面將逐個羅列！
while循環(huán)
let index = 0;const array = [1, 2, 3, 4, 5];while (index < array.length) { console.log(array[index]); index ;}
for循環(huán)
const array = [1,2,3,4,5];for(let index=0;index<array.length;index ){ console.log(array[index]);}for(let index in array){ console.log(array[index]);}
foreach
const array=[1,2,3,4,5];array.foreach(function(current_value,index,array){ console.log(`at index ${index} in array ${array} the value is ${current_value}`)})
map
最后一個構(gòu)造很有用，但是不會返回新數(shù)組，這對于你的特定情況可能是不希望的。map通過對每個元素應(yīng)用一個函數(shù)然后返回新數(shù)組來解決此問題。
const array = [1,2,3,4,5];const square = x =>math.pow(x,2);const squares = array.map(square);console.log(`${array}`);console.log(`${squares}`)
reduce
reduce()方法對累加器和數(shù)組中的每個元素(從左到右)應(yīng)用一個函數(shù)，以將其減小為單個值
const array = [1,2,3,4,5];const sum = (x,y) => x y;const array_sum = array.reduce(sum,0);console.log(`the sum of arrray:${array} is ${array_sum}`);
filter
根據(jù)布爾函數(shù)過濾篩選數(shù)組中的元素
const array = [1,2,3,4,5];const even = x => x%2 === 0;const even_array = array.filter(even);console.log(`even numbers in array ${array} : ${even_array}`);
every
得到了一個數(shù)組，想測試每個元素是否滿足給定條件
const array = [1,2,3,4,5,8];const under_six = x => x<6;if(array.every(under_six)){ console.log(`every elemnet in the array is less than 6`);}else{ console.log(`at least one element in the array was bigger than 6`);}
some
測試是否至少有一個元素與布爾函數(shù)匹配
const array = [2,4,5,6,8];const over_five = x => x>5;if(array.some(over_five)){ console.log(`at least one element bigger than 5 was found`);}else{ console.log(`no element bigger than 5 was found`);}
到此就結(jié)束啦，如果還有其他的歡迎補充！
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