map

_.map(collection, [iteratee=_.identity])

通过运行 collection 至 iteratee 中的每个元素创建一个值数组。迭代器使用三个参数调用：(value, index|key, collection)。

¥Creates an array of values by running each element in collection thru iteratee. The iteratee is invoked with three arguments: (value, index|key, collection).

许多 lodash 方法被保护起来，作为 _.every、_.filter、_.map、_.mapValues、_.reject 和 _.some 等方法的迭代器。

¥Many lodash methods are guarded to work as iteratees for methods like _.every, _.filter, _.map, _.mapValues, _.reject, and _.some.

初始值。ary、chunk、curry、curryRight、drop、dropRight、every、fill、invert、parseInt、random、range、rangeRight、repeat、sampleSize、slice、some、sortBy、split、take、takeRight、template、trim、trimEnd、trimStart 和 words

¥The guarded methods are: ary, chunk, curry, curryRight, drop, dropRight, every, fill, invert, parseInt, random, range, rangeRight, repeat, sampleSize, slice, some, sortBy, split, take, takeRight, template, trim, trimEnd, trimStart, and words

新增于

¥Since

0.1.0

参数

¥Arguments

1. collection (数组|对象)：要迭代的集合。

   ¥collection (Array|Object): The collection to iterate over.

2. [iteratee=_.identity] (函数)：每次迭代调用的函数。

   ¥[iteratee=_.identity] (Function): The function invoked per iteration.

返回

¥Returns

(数组)：返回新的映射数组。

¥(Array): Returns the new mapped array.

示例

¥Example

function square(n) {
  return n * n;
}

_.map([4, 8], square);
// => [16, 64]

_.map({ 'a': 4, 'b': 8 }, square);
// => [16, 64] (iteration order is not guaranteed)

var users = [
  { 'user': 'barney' },
  { 'user': 'fred' }
];

// The `_.property` iteratee shorthand.
_.map(users, 'user');
// => ['barney', 'fred']