convert string into array of integers
JavascriptJavascript Problem Overview
I want to convert the following string '14 2'
into an array of two integers.
How can I do it ?
Javascript Solutions
Solution 1 - Javascript
A quick one for modern browsers:
'14 2'.split(' ').map(Number);
// [14, 2]`
Solution 2 - Javascript
You can .split()
to get an array of strings, then loop through to convert them to numbers, like this:
var myArray = "14 2".split(" ");
for(var i=0; i<myArray.length; i++) { myArray[i] = +myArray[i]; }
//use myArray, it's an array of numbers
The +myArray[i]
is just a quick way to do the number conversion, if you're sure they're integers you can just do:
for(var i=0; i<myArray.length; i++) { myArray[i] = parseInt(myArray[i], 10); }
Solution 3 - Javascript
SO...older thread, I know, but...
#EDIT @RoccoMusolino had a nice catch; here's an alternative:
TL;DR:
const intArray = [...("5 6 7 69 foo 0".split(' ').filter(i => /\d/g.test(i)))]
WRONG: "5 6 note this foo".split(" ").map(Number).filter(Boolean); // [5, 6]
There is a subtle flaw in the more elegant solutions listed here, specifically @amillara and @Marcus' otherwise beautiful answers.
The problem occurs when an element of the string array isn't integer-like, perhaps in a case without validation on an input. For a contrived example...
The problem:
var effedIntArray = "5 6 7 69 foo".split(' ').map(Number); // [5, 6, 7, 69, NaN]
Since you obviously want a PURE int array, that's a problem. Honestly, I didn't catch this until I copy-pasted SO code into my script... :/
The (slightly-less-baller) fix:
var intArray = "5 6 7 69 foo".split(" ").map(Number).filter(Boolean); // [5, 6, 7, 69]
So, now even when you have crap int string, your output is a pure integer array. The others are really sexy in most cases, but I did want to offer my mostly rambly w'actually. It is still a one-liner though, to my credit...
Hope it saves someone time!
Solution 4 - Javascript
var result = "14 2".split(" ").map(function(x){return parseInt(x)});
Solution 5 - Javascript
An alternative to Tushar Gupta answer would be :
'14 2'.split(' ').map(x=>+x);
// [14, 2]`
In code golf you save 1 character. Here the "+" is "unary plus" operator, works like parseInt.
Solution 6 - Javascript
First split the string on spaces:
var result = '14 2'.split(' ');
Then convert the result array of strings into integers:
for (var i in result) {
result[i] = parseInt(result[i], 10);
}
Solution 7 - Javascript
The point against parseInt
-approach:
There's no need to use lambdas and/or give radix
parameter to parseInt
, just use parseFloat
or Number
instead.
Reasons:
-
It's working:
var src = "1,2,5,4,3"; var ids = src.split(',').map(parseFloat); // [1, 2, 5, 4, 3] var obj = {1: ..., 3: ..., 4: ..., 7: ...}; var keys= Object.keys(obj); // ["1", "3", "4", "7"] var ids = keys.map(parseFloat); // [1, 3, 4, 7] var arr = ["1", 5, "7", 11]; var ints= arr.map(parseFloat); // [1, 5, 7, 11] ints[1] === "5" // false ints[1] === 5 // true ints[2] === "7" // false ints[2] === 7 // true
-
It's shorter.
-
It's a tiny bit quickier and takes advantage of cache, when
parseInt
-approach - doesn't:// execution time measure function // keep it simple, yeah? > var f = (function (arr, c, n, m) { var i,t,m,s=n(); for(i=0;i++<c;)t=arr.map(m); return n()-s }).bind(null, "2,4,6,8,0,9,7,5,3,1".split(','), 1000000, Date.now); > f(Number) // first launch, just warming-up cache > 3971 // nice =) > f(Number) > 3964 // still the same > f(function(e){return+e}) > 5132 // yup, just little bit slower > f(function(e){return+e}) > 5112 // second run... and ok. > f(parseFloat) > 3727 // little bit quicker than .map(Number) > f(parseFloat) > 3737 // all ok > f(function(e){return parseInt(e,10)}) > 21852 // awww, how adorable... > f(function(e){return parseInt(e)}) > 22928 // maybe, without '10'?.. nope. > f(function(e){return parseInt(e)}) > 22769 // second run... and nothing changes. > f(Number) > 3873 // and again > f(parseFloat) > 3583 // and again > f(function(e){return+e}) > 4967 // and again > f(function(e){return parseInt(e,10)}) > 21649 // dammit 'parseInt'! >_<
Notice: In Firefox parseInt
works about 4 times faster, but still slower than others. In total: +e
< Number
< parseFloat
< parseInt
Solution 8 - Javascript
If the numbers can be separated by more than one space, it is safest to split the string on one or more consecutive whitespace characters (which includes tabs and regular spaces). With a regular expression, this would be \s+
.
You can then map
each element using the Number
function to convert it. Note that parseInt
will not work (i.e. arr.map(parseInt)
) because map
passes three arguments to the mapping function: the element, the index, and the original array. parseInt
accepts the base or radix as the second parameter, so it will end up taking the index as the base, often resulting in many NaN
s in the result. However, Number
ignores any arguments other than the first, so it works directly.
const str = '1\t\t2 3 4';
const result = str.split(/\s+/).map(Number); //[1,2,3,4]
To remove elements that are not numbers, Array#filter
can be used in conjunction with isNaN
.
const str = '1\t\t2 3 ab 4 c';
const result = str.split(/\s+/).map(Number).filter(x => !isNaN(x)); //[1,2,3,4]
You could also use an anonymous function for the mapping callback with the unary plus operator to convert each element to a number.
const str = '1\t\t2 3 4';
const result = str.split(/\s+/).map(x => +x); //[1,2,3,4]
With an anonymous function for the callback, you can decide what parameters to use, so parseInt
can also work.
const str = '1\t\t2 3 4';
const result = str.split(/\s+/).map(x => parseInt(x)); //[1,2,3,4]
Solution 9 - Javascript
Just for fun I thought I'd throw a forEach(f())
solution in too.
var a=[];
"14 2".split(" ").forEach(function(e){a.push(parseInt(e,10))});
// a = [14,2]
Solution 10 - Javascript
let idsArray = ids.split(',').map((x) => parseInt(x));
Solution 11 - Javascript
Better one line solution:
var answerInt = [];
var answerString = "1 2 3 4";
answerString.split(' ').forEach(function (item) {
answerInt.push(parseInt(item))
});
Solution 12 - Javascript
us the split function:
var splitresult = "14 2".split(" ");