强调了阵列_.pick等效 [英] Underscore equivalent of _.pick for arrays
问题描述
据我所知,挑来取回如果只指定属性的对象:
_挑({名称:'萌',年龄:50,用户id:'moe1'},'名','年龄');
= GT; {名称:'萌',年龄:50}
我将如何执行阵列上相同的操作,说我有一个数组,如:
[{名称:'moe1',年龄:50,用户id:'moe1},
{名称:'moe2',年龄:50,用户id:'moe1},
{名称:'moe3',年龄:50,用户id:'moe1'}]
和我想它映射到一个数组所以只包括名称
和年龄
属性,例如:
[{名称:'moe1',年龄:50},
{名称:'moe2',年龄:50},
{名称:'moe3',年龄:50}]
我必须做一个每()
对数组然后执行挑()
各个对象,或者是有一个更清洁的方式?
修改
很抱歉,但只是一个小要求,我将如何执行的地方(即获取所有那些年龄大于50),然后执行挑
?
修改
得到它这样做,不知道如何下划线链接的作品。
_(数据).reject(函数(R){返回d.age的51;})地图(功能(O){
返回_.pick(邻,年龄,姓名);
});
您必须使用 _。图
并应用相同的 _。挑
上的所有对象。
VAR数据= [{名称:'moe1',年龄:30,用户id:'moe1},
{名称:'moe2',年龄:50,用户id:'moe1},
{名称:'moe3',年龄:60,用户id:'moe1'}]VAR的结果= _.map(数据,功能(currentObject){
返回_.pick(currentObject,姓名,年龄);
});的console.log(结果);
输出
[{名称:'moe1',年龄:50},
{名称:'moe2',年龄:50},
{名称:'moe3',年龄:50}]
如果你想获得其中年龄> 50的对象,你可能想要做的,像这样
VAR数据= [{名称:'moe1',年龄:30,用户id:'moe1},
{名称:'moe2',年龄:50,用户id:'moe1},
{名称:'moe3',年龄:60,用户id:'moe1'}]功能filterByAge(currentObject){
返回currentObject.age&放大器;&安培; currentObject.age> 50;
}功能omitUserId(currentObject){
返回_.omit(currentObject,将把userid);
}VAR的结果= _.map(_过滤器(数据,filterByAge),omitUserId);
的console.log(结果);
输出
[{名称:'moe3',年龄:60}]
您可以做同样的链接,<一个href=\"http://stackoverflow.com/questions/22280775/underscore-equivalent-of-pick-for-arrays/22280789?noredirect=1#comment33847612_22280789\">as通过rightfold 建议,像这样
VAR的结果= _.chain(数据).filter(filterByAge).MAP(omitUserId).value的();
I understand that pick is used to get back an object with only specified properties:
_.pick({name: 'moe', age: 50, userid: 'moe1'}, 'name', 'age');
=> {name: 'moe', age: 50}
How would I perform that same operation on an array, say I have an array such as:
[{name: 'moe1', age: 50, userid: 'moe1'},
{name: 'moe2', age: 50, userid: 'moe1'},
{name: 'moe3', age: 50, userid: 'moe1'}]
and I want to map it to an array so to include only the name
and age
properties, like:
[{name: 'moe1', age: 50},
{name: 'moe2', age: 50},
{name: 'moe3', age: 50}]
Do I have to do an each()
on the array then perform a pick()
on each object, or is there a cleaner way?
EDIT
Sorry but just another small requirement, how would I perform a where (i.e. get all those whose age is greater than 50) and then perform the pick
?
EDIT
got it done like this, was unaware of how chaining works in underscore.
_(data).reject(function (r) { return d.age<51; }).map(function (o) {
return _.pick(o, "age", "name");
});
You have to use _.map
and apply the same _.pick
on all the objects.
var data = [{name: 'moe1', age: 30, userid: 'moe1'},
{name: 'moe2', age: 50, userid: 'moe1'},
{name: 'moe3', age: 60, userid: 'moe1'}];
var result = _.map(data, function(currentObject) {
return _.pick(currentObject, "name", "age");
});
console.log(result);
Output
[ { name: 'moe1', age: 50 },
{ name: 'moe2', age: 50 },
{ name: 'moe3', age: 50 } ]
If you want to get the objects in which the age is > 50, you might want to do, like this
var data = [{name: 'moe1', age: 30, userid: 'moe1'},
{name: 'moe2', age: 50, userid: 'moe1'},
{name: 'moe3', age: 60, userid: 'moe1'}];
function filterByAge(currentObject) {
return currentObject.age && currentObject.age > 50;
}
function omitUserId(currentObject) {
return _.omit(currentObject, "userid");
}
var result = _.map(_.filter(data, filterByAge), omitUserId);
console.log(result);
Output
[ { name: 'moe3', age: 60 } ]
You can do the same with chaining, as suggested by rightfold, like this
var result = _.chain(data).filter(filterByAge).map(omitUserId).value();
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