CODEWITHSUNDEEP
phparrays
Mooseman
Mooseman

Reputation: 18891

Search array keys with wildcard

Say I have the following array:

$arr = array(
   "number2"=>"valid",
   "number13"=>"valid"
);

and I need to find if there is a key that exists with number*.

For $arr, this would be true. For the following array:

$arr2 = array(
   "key"=>"foo",
   "key2"=>"foo2"
);

this would return false.

Upvotes: 7

Views: 15098

Answers (4)

Aydin4ik
Aydin4ik

Reputation: 1935

EPB and Dan Horrigan got it right, but from code cleanliness perspective, let me leave these here:

If you purely want to return true or false, you don't need an if statement; just return the result of the empty() check on the result of preg_grep():

return !empty(preg_grep('/^number[\d]*/', array_keys($arr));

If you need to run an 'if' check, count() or !empty() will return truthy/falsy already, you don't need to double-check their value:

if ( count( preg_grep('/^number[\d]*/', array_keys( $arr )) ) ) {
   // Action when it is true
} else {
   // Action when it is false
}

I personally prefer empty() over counting the result array elements, because type consistency:

if ( !empty( preg_grep('/^number[\d]*/', array_keys( $arr )) ) ) {
   // Action when it is true
} else {
   // Action when it is false
}

More on truthy/falsy, i.e. when a statement evaluates to true/false: https://www.php.net/manual/en/language.types.boolean.php

Upvotes: 0

EPB
EPB

Reputation: 4029

This one assumes number needs to be followed by an actual number (edit: or nothing at all), adjust the regular expression as necessary. For example, anything starting with 'number', you could use /^number/.

if(count(preg_grep('/^number[\d]*/', array_keys($arr))) > 0)
{
   return true;
}
else
{
   return false;
}

Upvotes: 5

Dan Horrigan
Dan Horrigan

Reputation: 1295

Here is a simple function which will do what you want:

function preg_grep_key($pattern, $input) {
    return preg_grep($pattern, array_keys($input));
}

// ----- Usage -----

$arr = array(
   "number2"=>"valid",
   "number13"=>"valid"
);


if (count(preg_grep_key('/^number/', $arr)) === 0) {
    // Nope
} else {
    // Yep
}

Upvotes: 0

Haver
Haver

Reputation: 443

Use regular expression.

foreach ($arr as $key => $value) {
  // NOTE: check for the right format of the regular expression 
  if (preg_match("/^number([0-9]*)$", $key)) {
    echo "A match was found.";
  } else {
    echo "A match was not found.";
  }
}

Upvotes: 2

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