Remove values with digit only from array - PHP - php

Question

I have an array like so
array(
1=>hello,
2=>foo,
3=>192,
4=>keep characters AND digits like a1e2r5,
);
All I want to do is to remove rows containing digits ONLY (3=>192), and return an array like this one :
array(
1=>hello,
2=>foo,
3=>keep characters AND digits like a1e2r5,
);
I tried with array_filter but didn't get it work. Can someone show me how to do? Thanks

Answer 1

$data = array( 1 => "hello",
2 => "foo",
3 => "192",
4 => "keep characters AND digits like a1e2r5",
);
$result = array_filter( $data,
function($arrayEntry) {
return !is_numeric($arrayEntry);
}
);
Or using slightly more modern PHP, with arrow functions:
$result = array_filter( $data,
fn($arrayEntry) => !is_numeric($arrayEntry)
);

Answer 2

You could use a loop and the intval function.
$filteredArray = array();
foreach($array as $element){
//this works because PHP is weakly typed
if(intval($element) != $element){
$filteredArray[] = $element;
}
}

Answer 3

Are you sure you were using array_filter correctly? It's the best solution for your problem.
// named callback for backwards compatibility, but use an anonymous function
// if you have a high enough php version.
function callback($item) { return !is_numeric($item); }
$result = array_filter($a, 'callback');
print_r($result);
// optional - causes numeric keys to be in order
$result = array_values($result);
print_r($result);
Output using example input from question as $a:
Array
(
[1] => hello
[2] => foo
[4] => keep characters AND digits like a1e2r5
)
Array
(
[1] => hello
[2] => foo
[3] => keep characters AND digits like a1e2r5
)

Answer 4

I'm surprised no one mentioned this in any of the answers: using numeric tests is not a total solution. Using numeric tests will remove some elements containing non-digit characters if they are evaluated as numeric. Specifically, {e, -, .}
$data=array(
1=>'hello',
2=>'foo',
3=>'192',
4=>'keep characters AND digits like a1e2r5',
5=>'1.4',
6=>'-42',
7=>'1e2',
8=>'1.23e4',
);
function callback1($arrayEntry) {
return !is_numeric($arrayEntry);
}
$result = array_filter( $data, 'callback1');
echo '<pre>';
print_r($result);
echo '<hr>';
function callback2($arrayEntry) {
return !preg_match('/^[0-9]+$/', $arrayEntry);
}
$result = array_filter( $data, 'callback2');
print_r($result);