How do I check if a word exists within a string in PHP?

How to Check Word Existence in a String Using PHP

To determine if a particular word exists within a string in PHP, you have various options based on your specific requirements.

Simple Check:

<code class="php">$needle = "to";
$haystack = "I go to school";

if (strpos($haystack, $needle) !== false) {
    echo "Found!";
}</code>

Here, strpos() is employed to locate the position of the word within the string. If found, it returns its index, prompting the if condition to execute and print "Found!".

Case-Insensitive Check:

<code class="php">if (stripos($haystack, $needle) !== false) {
    echo "Found!";
}</code>

stripos() performs the same operation as strpos() but ignores case differences, making it case-insensitive.

Advanced Matching:

If you require more flexibility in your search, consider using regular expressions:

<code class="php">if (preg_match("/to/", $haystack)) {
    echo "Found!";
}</code>

preg_match() allows you to define complex patterns to match instead of just a single word.

Complete Function:

For a standalone function that encapsulates the word existence check:

<code class="php">function match_my_string($needle = 'to', $haystack = 'I go to school') {
    if (strpos($haystack, $needle) !== false) return true;
    else return false;
}</code>

This function takes default values for the search word and string, but you can provide custom input.

PHP 8.0.0 Improvement:

In PHP 8.0.0 and later, you can utilize the str_contains() function, which simplifies the check significantly:

<code class="php">if (str_contains($haystack, $needle)) {
    echo "Found";
}</code>

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