JavaScript数组求和的5种常用方法

var arr = [1,2,3]; function sum(arr) { var s = 0; for (var i = 0;i
        

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var arr = [1,2,3]; function sum(arr) { var s = 0; arr.forEach(function(val, idx, arr) { s += val; }, 0); return s; }; console.log(sum(arr));//6

var arr = [1,2,3]; function sum(arr) { return arr.reduce(function(acr, cur){ return acr + cur; }); } console.log(sum(arr));//6

var arr = [1,2,3]; function sum(arr) { if(arr.length == 0){ return 0; } else if (arr.length == 1){ return arr[0]; } else { return arr[0] + sum(arr.slice(1)); } } console.log(sum(arr));//6

var arr = [1,2,3]; function sum(arr) { return eval(arr.join("+")); }; console.log(sum(arr));//6