The following code:
$string = "1,2,3"
$ids = explode(',', $string);
var_dump($ids);
Returns the array:
array(3) {
[0]=>
string(1) "1"
[1]=>
string(1) "2"
[2]=>
string(1) "3"
}
I need for the values to be of type int instead of type string. Is there a better way of doing this than looping through the array with foreach and converting each string to int?
You can achieve this by following code,
$integerIDs = array_map('intval', explode(',', $string));
So I was curious about the performance of some of the methods mentioned in the answers for large number of integers.
Just creating an array of 1 million random integers between 0 and 100. Than, I imploded them to get the string.
$integers = array();
for ($i = 0; $i < 1000000; $i++) {
$integers[] = rand(0, 100);
}
$long_string = implode(',', $integers);
This is the one liner from Mark's answer:
$integerIDs = array_map('intval', explode(',', $long_string));
This is the JSON approach:
$integerIDs = json_decode('[' . $long_string . ']', true);
I came up with this one as modification of Mark's answer. This is still using explode() function, but instead of calling array_map() I'm using regular foreach loop to do the work to avoid the overhead array_map() might have. I am also parsing with (int) vs intval(), but I tried both, and there is not much difference in terms of performance.
$result_array = array();
$strings_array = explode(',', $long_string);
foreach ($strings_array as $each_number) {
$result_array[] = (int) $each_number;
}
Method 1 Method 2 Method 3
0.4804770947 0.3608930111 0.3387751579
0.4748001099 0.363986969 0.3762528896
0.4625790119 0.3645150661 0.3335959911
0.5065748692 0.3570590019 0.3365750313
0.4803431034 0.4135499001 0.3330330849
0.4510772228 0.4421861172 0.341176033
0.503674984 0.3612480164 0.3561749458
0.5598649979 0.352314949 0.3766179085
0.4573421478 0.3527538776 0.3473439217
0.4863037268 0.3742785454 0.3488383293
The bottom line is the average. It looks like the first method was a little slower for 1 million integers, but I didn't notice 3x performance gain of Method 2 as stated in the answer. It turned out foreach loop was the quickest one in my case. I've done the benchmarking with Xdebug.
Edit: It's been a while since the answer was originally posted. To clarify, the benchmark was done in php 5.6.40.
array_map(function($v){ return (int)$v; }, $strings_array); this is what I meant –
Rigorous Convert a comma-delimited string into array of integers?. I guess my understanding of this, is Convert a string of comma-delimited integers into array of integers (which seems to be in line with understanding of this question by other responders). You claim the question is Convert array values from string to int. Nowhere in the OP post I see, that he starts with an array. I do see $string = "1,2,3" on the first line of code, which would imply that the staring point is a string of comma delimited integers. –
Zebulon This is almost 3 times faster than explode(), array_map() and intval():
$integerIDs = json_decode('[' . $string . ']', true);
str_replace will do that.. I think then also this is faster.. right? –
Amitosis float number and not only to integer, and you guys didn't realize it. –
Mockery boolean :-) –
Phenobarbital Use this code with a closure (introduced in PHP 5.3), it's a bit faster than the accepted answer and for me, the intention to cast it to an integer, is clearer:
// if you have your values in the format '1,2,3,4', use this before:
// $stringArray = explode(',', '1,2,3,4');
$stringArray = ['1', '2', '3', '4'];
$intArray = array_map(
function($value) { return (int)$value; },
$stringArray
);
var_dump($intArray);
Output will be:
array(4) {
[0]=>
int(1)
[1]=>
int(2)
[2]=>
int(3)
[3]=>
int(4)
}
In Mark's solution, you will return array([0]=> int 0) if you try to parse a string such as "test".
$integerIDs = array_map( 'intval', array_filter( explode(',', $string), 'is_numeric' ) );
An alternative shorter method could be:
$r = explode(',', $s);
foreach ($r as &$i) $i = (int) $i;
It has the same performance as Method 3.
My solution is casting each value with the help of callback function:
$ids = array_map( function($value) { return (int)$value; }, $ids )
$ids = \array_map(fn(string $id): int => (int) $id, $ids); - even nicer with PHP 7.4+ –
Enrich Not sure if this is faster but flipping an array twice will cast numeric strings to integers:
$string = "1,2,3,bla";
$ids = array_flip(array_flip(explode(',', $string)));
var_dump($ids);
Important: Do not use this if you are dealing with duplicate values!
bla as an integer, it is incorrect and I must DV. This answer doesn't satisfy the question title. –
Tennilletennis If you have array like:
$runners = ["1","2","3","4"];
And if you want to covert them into integers and keep within array, following should do the job:
$newArray = array_map( create_function('$value', 'return (int)$value;'),
$runners);
create_function is deprecated, you can do this instead: $newArray = array_map(fn($value) => (int) $value, $runners) –
Liquidambar PHP 7.4 style:
$ids = array_map(fn(string $x): int => (int) $x, explode(',', $string));
Keep it simple...
$intArray = array ();
$strArray = explode(',', $string);
foreach ($strArray as $value)
$intArray [] = intval ($value);
Why are you looking for other ways? Looping does the job without pain. If performance is your concern, you can go with json_decode (). People have posted how to use that, so I am not including it here.
Note: When using == operator instead of === , your string values are automatically converted into numbers (e.g. integer or double) if they form a valid number without quotes. For example:
$str = '1';
($str == 1) // true but
($str === 1) //false
Thus, == may solve your problem, is efficient, but will break if you use === in comparisons.
If you have a multi-dimensional array, none of the previously mentioned solutions will work. Here is my solution:
public function arrayValuesToInt(&$array){
if(is_array($array)){
foreach($array as &$arrayPiece){
arrayValuesToInt($arrayPiece);
}
}else{
$array = intval($array);
}
}
Then, just do this:
arrayValuesToInt($multiDimentionalArray);
This will make an array like this:
[["1","2"]["3","4"]]
look like this:
[[1,2][3,4]]
This will work with any level of depth.
Alternatively, you can use array_walk_recursive() for a shorter answer:
array_walk_recursive($array, function(&$value){
$value = intval($value);
});
array function that walks recursively through leaf nodes. –
Tennilletennis array_walk_recursive.... it is a "shorter" solution. Forgot about that one, thanks. (added to answer) –
Tansy $arr = ["adfsf", "*&^%$#^", "23", "25", "29"];
function convertArrayStringToArrayInt($arr)
{
$result = [];
foreach($arr as $value) {
if ((int)$value !== 0) {
$result[] = (int)$value;
}
}
return $result;
}
$result = convertArrayStringToArrayInt($arr);
var_dump($result);
The result will be like this
array(3) {
[0]=> int(23)
[1]=> int(25)
[2]=> int(29)
}
Input => '["3","6","16","120"]'
Type conversion I used => (int)$s;
function Str_Int_Arr($data){
$h=[];
$arr=substr($data,1,-1);
//$exp=str_replace( ",","", $arr);
$exp=str_replace( "\"","", $arr);
$s='';
$m=0;
foreach (str_split($exp) as $k){
if('0'<= $k && '9'>$k || $k =","){
if('0' <= $k && '9' > $k){
$s.=$k;
$h[$m]=(int)$s;
}else{
$s="";
$m+=1;
}
}
}
return $h;
}
var_dump(Str_Int_Arr('["3","6","16","120"]'));
Output:
array(4) {
[0]=>
int(3)
[1]=>
int(6)
[2]=>
int(16)
[3]=>
int(120)
}
Thanks
<?php
$string = "1,2,3";
$ids = explode(',', $string );
array_walk( $ids, function ( &$id )
{
$id = (int) $id;
});
var_dump( $ids );
I'm surprised no one proposed filter_var method, I'm not sure how well it performs on huge datasets, but if your key is validity over performance here is an example:
$sampleString = '1,2 3, 4, 6, 5 , a';
$filteredValues = filter_var(
explode(',', $sampleString),
FILTER_VALIDATE_INT,
FILTER_NULL_ON_FAILURE | FILTER_FORCE_ARRAY
);
array (size=6)
0 => int 1
1 => null
2 => int 4
3 => int 6
4 => int 5
5 => null
As you can see 2 3 is not a valid number same as a and were replaced by null
To get rid of empty values you can apply array_filter
$filteredValues = array_filter($filteredValues);
which would produce following result:
array (size=4)
0 => int 1
2 => int 4
3 => int 6
4 => int 5
I have a solution to some reader, I made bit change from Mr. Mark Baker solution above
For user having problems with arrays, using Laravel PHP here is the tweak
$originalArray = $data->pluck('column')->toArray();
$convertedString = implode(', ', $originalArray);
$data = array_map('intval', explode(',', $convertedString ));
var_dump($data);
This method worked for me, maybe it will help you
$id = array_map(static fn($key) => (int)$key, $id);
Another technique is to type-hint (coerce) the incoming values to int type after exploding the string.
Note that these techniques will work as demonstrated in my demo link unless you have set php to use strict typing.
The following techniques should not be used to sanitize non-numeric strings; it assumes that all values will be numeric.
If float values are passed into these techniques, they will be truncated/floored to integers.
Code: (Demo)
$string = "1,2,3";
$array = explode(',', $string);
var_dump($array);
echo "\n---\n";
array_walk($array, function(int &$int){;});
var_dump($array);
echo "\n---\n";
var_dump(
array_map(function(int $i){ return $i; }, explode(',', $string))
);
echo "\n---\n";
var_dump(
array_map(fn(int $i) => $i, explode(',', $string)) // PHP 7.4 arrow function syntax
);
Output:
array(3) {
[0]=> string(1) "1"
[1]=> string(1) "2"
[2]=> string(1) "3"
}
---
array(3) {
[0]=> int(1)
[1]=> int(2)
[2]=> int(3)
}
---
array(3) {
[0]=> int(1)
[1]=> int(2)
[2]=> int(3)
}
---
array(3) {
[0]=> int(1)
[1]=> int(2)
[2]=> int(3)
}
intval() is going to be the better solution, and that's already the accepted answer, so this answer doesn't add any value. –
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