Javascript Array：获取项目的“范围”
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Javascript Array: get 'range' of items
提问by shdev
Is there an equivalent for ruby's array[n..m] in Javascript ?
Javascript 中 ruby 的数组[n..m] 是否有等价物？
For example:
例如：
>> a = ['a','b','c','d','e','f','g']
>> a[0..2]
=> ['a','b','c']
Thanks
谢谢
回答by Vivin Paliath
Use the array.slice(begin [, end])function.
使用该array.slice(begin [, end])功能。
var a = ['a','b','c','d','e','f','g'];
var sliced = a.slice(0, 3); //will contain ['a', 'b', 'c']
The last index is non-inclusive;to mimic ruby's behavior you have to increment the endvalue. So I guess slicebehaves more like a[m...n]in ruby.
最后一个索引是非包含的；要模仿 ruby 的行为，您必须增加该end值。所以我猜它的slice行为更像是a[m...n]在 ruby 中。
回答by Robert
a.slice(0, 3)Would be the equivalent of your function in your example.
a.slice(0, 3)将相当于您的示例中的功能。
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/slice
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/slice
回答by David Hoerster
The second argument in sliceis optional, too:
in 中的第二个参数slice也是可选的：
var fruits = ['apple','banana','peach','plum','pear'];
var slice1 = fruits.slice(1, 3); //banana, peach, plum
var slice2 = fruits.slice(3); //plum, pear
You can also pass a negative number, which selects from the end of the array:
您还可以传递一个负数，它从数组的末尾选择：
var slice3 = fruits.slice(-3); //peach, plum, pear
Here's the W3 Schools reference link.
这是 W3 学校参考链接。
回答by Douglas
Ruby and Javascript both have a slice method, but watch out that the second argument to slice in Ruby is the length, but in JavaScript it is the index of the last element:
Ruby 和 Javascript 都有slice 方法，但要注意 Ruby 中 slice 的第二个参数是长度，但在 JavaScript 中它是最后一个元素的索引：
var shortArray = array.slice(start, end);
