How to Extract Specific Words from a String in PHP?

Extracting Specific Words from a String

When working with text data in programming, it's often necessary to extract specific words or phrases from a given string. For instance, you might want to display a preview of the first few words of an article or create a word cloud from a large body of text.

Get First N Words from a String

Suppose you want to obtain only the first 10 words from the sentence, "The quick brown fox jumped over the lazy dog." Without relying on built-in string functions that may have limitations, you can use a combination of array manipulation and regular expressions to achieve this:

<code class="php">// Split the string into individual words
$words = explode(' ', $sentence);

// Slice the array to select the first N words
$first_n_words = array_slice($words, 0, 10);

// Implode the array back into a string
$excerpt = implode(' ', $first_n_words);

echo $excerpt; // "The quick brown fox jumped over"</code>

This approach effectively extracts the desired words and stores them in the $excerpt variable.

Supporting Other Word Breaks

The above solution works well for simple whitespace-separated words. However, if your string contains different word breaks such as commas or dashes, you can use regular expressions to handle them:

<code class="php">function get_words($sentence, $count = 10) {
  preg_match("/(?:\w+(?:\W+|$)){0,$count}/", $sentence, $matches);
  return $matches[0];
}

$words = get_words($sentence, 10);
echo $words; // "The, quick, brown, fox, jumped, over, the, lazy"</code>

Unicode Considerations

PHP's default regular expression functions may not handle Unicode characters properly. To support UTF-8 or Unicode, you can replace w and W in the above expressions with appropriate Unicode-aware character classes.

Conclusion

By using these techniques, you can extract specific words from a given string, regardless of the word break or Unicode considerations.

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