如何向对象添加数组，但是为每个数组元素过滤除了一列以外的所有数组？

Question

I have an array on my page called answers that looks like this:

answers[{x: 1, r: true;},{x: 2,r: false;},{x: 3, r: true;}]

Hopefully I wrote this correctly. There are a variable number of rows in the answers array (this time it's three but it could be anything under ten). Each row contains an x field and a r field.

Can someone tell me how I can add the answers array (or recreate another similar one) but ONLY the r field of each row of the answers array to the following object:

$scope.so.xHeaders[fromParams]

Answer 1

你可以在Underscore.js中使用pluck方法：

var newList = _.pluck(answers, 'r');

Answer 2

You can do something like that:

$scope.so.xHeaders = []
angular.forEach(answers, function(value, index) {
    $scope.so.xHeaders.push({ r: value.r });
});

Answer 3

Depending on what you need there are a couple of ways of doing this.

var answers = [{x: 1, r: true},{x: 2, r: false},{x: 3, r: true}]

1) If you just want an array of values:

var arr = answers.map(function(el){
  return el.r;
}, []);

console.log(arr) // [true, false, true]

2) If you want to return the objects but only containing the r value:

var arr = answers.map(function(el){
  var obj = {};
  obj.r = el.r;
  return obj;
}, []);

(or shorter):

var arr = answers.map(function(el){
  return { r: el.r };
}, []);

console.log(arr) // [Object { r=true}, Object { r=false}, Object { r=true}]

Fiddle .