How to Check If a Word Exists in a String in PHP?

How to Determine the Presence of a Word in a String Using PHP

You seek a PHP function that verifies the existence of a specific word within a larger string. Consider the following pseudocode:

text = "I go to school"
word = "to"
if (word.exist(text)) {
    return true
else {
    return false
}

To fulfill this requirement, PHP offers several functions that cater to different scenarios.

Using strpos()

For simple instances where you only need to ascertain the word's presence, strpos() provides a straightforward approach:

<code class="php">$needle = "to";  // The word you're searching for
$haystack = "I go to school";  // The string to be searched

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

Using strstr()

If you need to perform further actions based on the result, strstr() offers more flexibility:

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

Using preg_match()

For complex patterns involving regular expressions, preg_match() is suitable:

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

Defining a Custom Function

To package these capabilities into a custom function with default values for needle and haystack:

<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>

Using str_contains() (PHP 8.0.0 and above)

PHP 8.0.0 introduced str_contains():

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

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