PHP Regular Expression Exercises: Checks whether a string contains another string

Last update on May 31 2025 12:57:41 (UTC/GMT +8 hours)

1. Check if a string contains another string

Write a PHP script that checks whether a string contains another string.

Visual Presentation:

PHP Regular Expression Exercise: Checks whether a string contains another string

Sample Solution:

PHP Code:

<?php
// Define the regular expression pattern to match 'fox' preceded by a word character and followed by a space
$pattern = '/[^\w]fox\s/';

// Use preg_match function to check if the pattern matches the given string
if (preg_match($pattern, 'The quick brown fox jumps over the lazy dog')) {
    // If 'fox' is found in the string, echo that it is present
    echo "'fox' is present..."."\n";
} else {
    // If 'fox' is not found in the string, echo that it is not present
    echo "'fox' is not present..."."\n";
}
?>

Output:

'fox' is present...

Explanation:

In the exercise above,

A regular expression pattern is defined using the '$pattern' variable. The pattern /[^\w]fox\s/ is used, which matches the word "fox" preceded by a non-word character and followed by a space.
The "preg_match()" function checks if the pattern matches the given string 'The quick brown fox jumps over the lazy dog'.
If the pattern matches the string, meaning the word "fox" is found as per the defined pattern, it echoes "'fox' is present...".
If the pattern doesn't match the string, meaning the word "fox" is not found as per the defined pattern, it echoes "'fox' is not present...".

Flowchart :

For more Practice: Solve these Related Problems:

Write a PHP script to find and count the number of occurrences of a substring within a given string, ignoring case sensitivity.
Write a PHP script to check if any of the strings in an array exist as substrings in a given sentence.
Write a PHP function to determine whether a given string contains multiple occurrences of a specific word and return their positions.
Write a PHP script to identify if a keyword appears at the beginning or end of a string, considering both cases and word boundaries.

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