Is there an equivalent for ruby's array[n..m] in JavaScript?
For example:
>> a = ['a','b','c','d','e','f','g']
>> a[0..2]
=> ['a','b','c']
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3yes, coffeescript! New-and-improved range, slice, splice and loop syntax.Lance Pollard– Lance Pollard2011-05-18 23:02:40 +00:00Commented May 18, 2011 at 23:02
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4 Answers
Use the array.slice(begin [, end]) function.
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 end value. So I guess slice behaves more like a[m...n] in ruby.
1 Comment
pasx
>The last index is non-inclusive< Put that sentence in bold (:
The second argument in slice is optional, too:
var fruits = ['apple','banana','peach','plum','pear'];
var slice1 = fruits.slice(1, 3); //banana, peach
var slice2 = fruits.slice(3); //plum, pear
You can also pass a negative number, which selects from the end of the array:
var slice3 = fruits.slice(-3); //peach, plum, pear
Here's the W3 Schools reference link.
1 Comment
Bobby Jack
How about linking to Mozilla's javascript reference, which is far more informative and much better written than the W3 schools site (which has nothing to do with the W3C)? developer.mozilla.org/en/JavaScript/Reference/Global_Objects/…
a.slice(0, 3) Would be the equivalent of your function in your example.
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/slice
1 Comment
Anurag
actually it would be
a.slice(0, 3). slice in JavaScript doesn't included the end index.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:
var shortArray = array.slice(start, end);
