Question

我使用map从多维数组中获取数组。以下是我的代码

 var data = [{"name":"ramu","id":"719","gmail":"ramu@gmail.com","ph":988989898,"points":36},
        {"name":"ravi","id":"445","gmail":"ravi@gmail.com","ph":4554545454,"points":122},
        {"name":"karthik","id":"866","gmail":"karthik@gmail.com","ph":2332233232,"points":25}]          
var result = data.map(function(arr, count) { 
  return arr.points;
});

输出为[36,122,25]。但我需要总和为183？

Answer 1

使用Array#reduce方法获取属性的总和。

var data = [{"name":"ramu","id":"719","gmail":"ramu@gmail.com","ph":988989898,"points":36},
        {"name":"ravi","id":"445","gmail":"ravi@gmail.com","ph":4554545454,"points":122},
        {"name":"karthik","id":"866","gmail":"karthik@gmail.com","ph":2332233232,"points":25}]          


var result = data.reduce(function(tot, arr) { 
  // return the sum with previous value
  return tot + arr.points;

  // set initial value as 0
},0);

console.log(result);

Answer 2

只需在原始代码后面写下以下代码

var result = result.reduce(add, 0);

function add(a, b) {
    return a + b;
}

console.log(result);

Answer 3

使用数组＆＃39; reduce()，如下所示：

＆＃13;

var data = [{"name":"ramu","id":"719","gmail":"ramu@gmail.com","ph":988989898,"points":36},
	{"name":"ravi","id":"445","gmail":"ravi@gmail.com","ph":4554545454,"points":122},
	{"name":"karthik","id":"866","gmail":"karthik@gmail.com","ph":2332233232,"points":25}]          
var result = data.reduce(function(sum, item){
	return sum = sum+item.points;
},0);

console.log(result);

＆＃13;

使用javascript动态地从地图结果中求和数组

3 个答案: