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es6 method to implement array summation: 1. Use the reduce() method, syntax "arr.reduce(function(p,c){sum=p c;});"; 2. Use forEach() Method, syntax "arr.forEach(function(v){sum =v})".
The operating environment of this tutorial: Windows 7 system, ECMAScript version 6, Dell G3 computer.
In es6, you can use the new array traversal methods reduce() and forEach() to perform array summation. Let’s learn more about it below.
Method 1: Use the reduce() method
reduce can traverse the array, let the two items before and after the array perform some calculation, and then return its value and continue the calculation. , does not change the original array, and returns the final result of the calculation; if no initial value is given, the traversal starts from the second item of the array.
The reduce() method receives a function as an accumulator, and each value in the array (from left to right) starts to be reduced and finally calculated to a value.
Example: Use the reduce() method to perform array sum
var arr = [11, 12, 13], sum = 0; arr.reduce(function(pre,curr) { sum=pre+curr; return sum; }); console.log(sum);
Method 2: Use the forEach() method
The forEach() method is used to call each element of the array and pass the element to the callback function.
In the callback function, you can perform a summation operation to add up all the passed array elements.
Example: Accumulate and sum array values
var arr = [1, 2, 3], sum = 0; arr.forEach(function(value) { sum += value; }); console.log(sum);
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