How to delete specified content of array in php regular code

In PHP, regular expressions are a very useful tool that can be used to easily search, replace, and delete operations in strings. Regular expressions can also be used to match and delete elements in arrays.

This article will introduce how to use regular expressions to delete specified content from a PHP array.

1. PHP Array

In PHP, an array is a data structure used to store multiple values. Each element of the array can be any data type, such as strings and numbers. , Boolean, etc. There are two types of PHP arrays: associative arrays and indexed arrays.

Associative arrays are arrays that access array elements by specifying key names. They are often used to store configuration information, data table rows, etc. An indexed array is a collection of elements compiled in order, and each element can be accessed through its corresponding index number.

2. PHP regular expressions

In PHP, regular expressions are tools that describe text patterns through character sequences. Regular expressions are commonly used to search, replace, filter, and validate strings.

Use the preg function in PHP to process regular expressions. The following is the structure of the preg function:

int preg_match(string $pattern, string $subject [, array &$matches [, int $flags = 0 [, int $offset = 0 ]]])

The first parameter $pattern represents the regular expression to be matched.

The second parameter $subject represents the string to be matched.

The third parameter $matches is an array used to store all matching results.

The fourth parameter $flags contains optional flags used to specify matching behavior.

The fifth parameter $offset indicates the position in the $subject string to start matching.

3. Delete the specified content in the array

PHP array provides some functions to process array elements, such as array_push, array_pop, array_shift, array_unshift, etc. However, these functions can only process elements in the array and cannot delete specified content through regular expressions.

In order to delete the specified content from the PHP array, you can use the following code:

function delete_array_elements(&$array, $pattern) {
    foreach($array as $key => $value) {
        if(preg_match($pattern, $value)) {
            unset($array[$key]);
        }
    }
}

In the above code, the delete_array_elements function accepts an array and a regular expression as parameters, Iterate through each element in the array, use the preg_match function to match the element and the regular expression, and if the match is successful, use the unset command in PHP to remove the element from the array.

4. Example

The following is an example showing how to use the delete_array_elements function to delete specified content in an array.

$array = array("apple", "kiwi", "banana", "pear", "grape");
$pattern = "/^a.*/";

delete_array_elements($array, $pattern);

print_r($array);

In the above code, we create an array containing strings and define a regular expression starting with the letters a. Call the delete_array_elements function, passing $array and $pattern as arguments to it.

Run the above code, the output result is:

Array
(
    [1] => kiwi
    [3] => pear
    [4] => grape
)

You can see that the elements "apple" and "banana" starting with the letters a have been removed from $array was deleted from the array.

5. Summary

PHP regular expressions provide powerful text processing functions that can be used to search, replace and delete specified content in strings. Using regular expressions, we can easily remove specified content from PHP arrays, which is very useful for data processing. In the process of using regular expressions, we need to pay attention to selecting appropriate regular expressions and correctly using regular expression related functions.

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