Cast all digital values in array as integer-type, otherwise leave non-digital values as strings

Question

Given an array, how do I convert array starting at key [1] from type string to type int?

Array
(
  [0] => "id"
  [1] => "6086220176"
  [2] => "6542925762"
  [3] => "6623113406"
  [4] => "6702782948"
)

I've checked out related question how to convert array values from string to int? already, but I would like to skip the first key "id" int he conversion, and not all keys in array!

Do you want to convert based on the key value (being >=1) or based on the value itself (being of numeric type)? What have you attempted so far to make this happen? — Mike Brant, Nov 08 '13 at 16:53
I just have to ask ... why? PHP is loosely typed, it makes pretty much no difference how the data is stored in the array, just cast it (if necessary) as and when you need to use it, surely? — CD001, Nov 08 '13 at 16:55
@CD001 Well it has its uses as a cheap and easy sanitatizer. For example i have a pagination script and the target urls have the `page=n` on them and it's cheap and easy to just cast `page` as int. — CrayonViolent, Nov 08 '13 at 17:01
@CrayonViolent ... I'm not saying don't cast to (int), (float) or whatever ... but I'm not sure I can see the value of casting all the values in an array to a specific type and stuffing them back into the array ... surely at some point you're doing something with them and at *that* moment why not cast them? `if($something === (int) $array[2]) { ... }` for example... — CD001, Nov 08 '13 at 17:05
Is `$array[0]` "id" the literal string "id" or is it itself a number and you're just using a placeholder example? reason i ask is because several of the answers below won't work if `[0]` itself is also numeric @user1899415 — CrayonViolent, Nov 08 '13 at 17:07
@CD001 fair enough, i guess i didn't read your comment hard enough — CrayonViolent, Nov 08 '13 at 17:09

Paulo Freitas · Answer 1 · 2013-11-08T17:02:05.400

5

array_walk($array, function (&$value) {
    if (ctype_digit($value)) {
        $value = (int) $value;
    }
});
var_export($array);

Output:

array (
  0 => 'id',
  1 => 6086220176,
  2 => 6542925762,
  3 => 6623113406,
  4 => 6702782948,
)

edited Nov 08 '13 at 17:02

answered Nov 08 '13 at 16:55

Paulo Freitas

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score 3 · Answer 2 · answered Nov 08 '13 at 16:59

3

$array = array($array[0]) + array_map('intval', $array);

(if you want to avoid a foreach loop)

answered Nov 08 '13 at 16:59

nice ass

16,471
7
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score 3 · Accepted Answer · answered Nov 08 '13 at 17:11

3

$arr = array_merge(array($arr[0]),array_map('intval', array_slice($arr, 1)));

Output:

array(5) {
  [0]=>
  string(2) "id"
  [1]=>
  int(2147483647)
  [2]=>
  int(2147483647)
  [3]=>
  int(2147483647)
  [4]=>
  int(2147483647)
}

Demo.

answered Nov 08 '13 at 17:11

Amal Murali

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score 0 · Answer 4 · answered Nov 08 '13 at 16:54

0

php is loosely typed, you don't need to type cast it. It will do it for you. But if you want to explicitly do this, you can do like this:

$c = count($array)-1;
for ($n=1;$n<$c;$n++) {
  $array[$n] = (int) $array[$n];
}

answered Nov 08 '13 at 16:54

CrayonViolent

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score 0 · Answer 5 · answered Nov 08 '13 at 16:55

0

foreach($array as $key => $val){
    if($key !== 0){
        $array[$key] = (int) $val;
    }
}

or

foreach($array as $key => $val){
    if(is_numeric($val)){
        $array[$key] = (int) $val;
    }
}

answered Nov 08 '13 at 16:55

Wayne Whitty

19,513
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score 0 · Answer 6 · answered Nov 08 '13 at 16:56

If all you values are int :

<?php
$arr = array(
  [0] => "id"
  [1] => "6086220176"
  [2] => "6542925762"
  [3] => "6623113406"
  [4] => "6702782948"
);

$arr = array_map(function($var) {
    // Your 'id' is not an int and will not be converted.
    return is_numeric($var) ? (int)$var : $var;
}, $arr);

score 0 · Answer 7 · answered Nov 08 '13 at 16:58

foreach($array as $k => $v){
  if($k == 0) continue;
  $array[$k] = is_int($v) ? intval($v) : $v; // if it's not convertible to int it keeps the value
}

or if you have non-numeric indexes

$skipped = false;
foreach($array as $k => $v){
  if($skipped === false){
    $skipped = true;
    continue;
  }
  $array[$k] = is_int($v) ? intval($v) : $v;
}

mickmackusa · Answer 8 · 2022-05-15T11:51:36.800

Another technique not yet mentioned on this page is to encode the array as a json string with the JSON_NUMERIC_CHECK flag so that numeric values are appropriately cast as integers or floats. Then decode the generated string back to an array.

This approach does not require the developer to know in advance the key/index of the value nor require a conditional check on each value to see if the value is numeric. In simple terms, it is highly portable as a general-use strategy.

This technique conveniently accommodates arrays with more than one level.

Code: (Demo)

$array = [
  "id",
  "6086220176",
  "6542925762",
  "6623113406",
  "6702782948",
  ['333', [['444']]]
];

var_export(
    json_decode(
        json_encode(
            $array,
            JSON_NUMERIC_CHECK
        ),
        true
    )
);

Output:

array (
  0 => 'id',
  1 => 6086220176,
  2 => 6542925762,
  3 => 6623113406,
  4 => 6702782948,
  5 => 
  array (
    0 => 333,
    1 => 
    array (
      0 => 
      array (
        0 => 444,
      ),
    ),
  ),
)

score -1 · Answer 9 · answered Nov 08 '13 at 16:53

-1

It's not clever to do this but this could probably works:

$narray = array();
foreach($array as $k => $v){
   $narray[$k+1] = $v;
}
$array = $narray;

$array is your array you want to start with 1.

answered Nov 08 '13 at 16:53

idmean

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Cast all digital values in array as integer-type, otherwise leave non-digital values as strings

9 Answers9