How to determine whether there is a certain dimension array in a two-dimensional array in PHP

In PHP, processing multi-dimensional arrays is one of the common tasks. For a two-dimensional array, we sometimes need to find a one-dimensional array containing a specific element. So how to achieve it?

Method 1: Use the in_array function

PHP’s built-in in_array function can find whether a specific element is contained in a one-dimensional array. So for a two-dimensional array, we can loop through the one-dimensional array and call the in_array function to search respectively. If found, it will return true, otherwise it will return false.

The following is the sample code:

function searchSubArrayInArray($needle, $haystack) {
  foreach ($haystack as $subArray) {
    if (in_array($needle, $subArray)) {
      return true;
    }
  }
  return false;
}

In the above example, $needle represents the one-dimensional array to be searched, and $haystack represents the two-dimensional array to be searched. This function returns a bool type value indicating whether it exists.

It should be noted that the in_array function is case-sensitive, so you need to pay attention to the case when using it.

Method 2: Use the array_search function

In addition to the in_array function, PHP also provides another way to find elements: the array_search function. This function searches an array for a given value and, if found, returns the key for that value (i.e. a one-dimensional array). Returns false if not found.

The following is the sample code:

function searchSubArrayInArray($needle, $haystack) {
  foreach ($haystack as $key => $subArray) {
    if (array_search($needle, $subArray) !== false) {
      return $key;
    }
  }
  return false;
}

In the above example, $needle represents the one-dimensional array to be searched, and $haystack represents the two-dimensional array to be searched. This function returns an int type value (that is, the key of the one-dimensional array containing needle in the two-dimensional array), or false.

It should be noted that if multiple one-dimensional arrays contain needle elements, the array_search function will only return the first matching key.

Summary

The above are two common methods to determine whether a two-dimensional array contains a one-dimensional array. If it needs to be used in actual projects, different methods need to be selected according to the actual situation.

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