What is the best way to convert the string values to an int array, e.g.:
var s = '1,1,2';
to:
var a = [1,1,2];
Thanks
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Do you trust the values in the string array or do you need to validate that each value is numeric?jball– jball2011-02-10 16:58:29 +00:00Commented Feb 10, 2011 at 16:58
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I was thinking about using split then parseInt to make sure, the values should be ok thoughxylar– xylar2011-02-10 17:01:56 +00:00Commented Feb 10, 2011 at 17:01
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If you trust the values, the solution in the first part of @Andy E's answer is the simplest and quickest.jball– jball2011-02-10 17:04:51 +00:00Commented Feb 10, 2011 at 17:04
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3 Answers
"1,2,3".split(",").map(Number);
And for those browsers that don't implement map, take an implementation like this one from here: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/map
Array.prototype.map is in ECMAScript5, so don't be afraid to augment Array.prototype.
JavaScript is a dynamic-typed language, which means that it might not be so important for those array items to be numbers. If that's the case, you might want to consider just using split():
var s = '1,1,2',
a = s.split(",");
If it is important that they're numbers, then your best bet is to iterate over them afterwards:
for (var i = 0, max = a.length; i < max; i++)
a[i] = +a[i];
There's also the ECMAScript 5th Edition method map, but it's not implemented in all browsers yet.
3 Comments
Rachel McMahan
Do you need to validate the strings are numeric first or do you already know that they'll be valid?
xylar
Thanks, is there an advantage of using
a[i] = +a[i]; over a[i] = parseInt(a[i])?
Andy E
@xylar: without a second argument for
parseInt, there's a potential danger of numbers starting with a 0 being parsed as octals. +a[i] is the equivalent of Number(a[i]), which always parses as decimal unless the number starts with 0x (for hex). Mostly, though, I use it because it's shorter :-)If the data is secure, you could use .eval().
var a = eval( '[' + s + ']');
If you're not sure about security, you could use JSON.parse.
var a = JSON.parse( "[" + s + "]" );
...though you'll need to include a parser in browsers that don't support it natively.
2 Comments
Andy E
Forewarning that if any of the values were invalid, a syntax error would be thrown - e.g.
1,2,3a,4. If you can trust the source, then I quite like the JSON.parse approach.
user113716
@Andy E: Good point. This works if you're expecting valid numbers. Though if something invalid finds its way in, a syntax error may be desired. Depends on how this is used I guess. :o)