Create a array of words using preg_match_all and regular expression

Question

I'm using the PHP function preg_match_all() like below to create an array which contains multiple words.

// the string which contains the text 
$string = "Lorem ipsum dolor sit amet elit";

// the preg_match_all() function
preg_match_all('/([a-z]*?)(?= )/i', $string, $matches);

// debug array
debug($matches[0]);

// output
[(int) 0 => 'Lorem',
    (int) 1 => '',
    (int) 2 => 'ipsum',
    (int) 3 => '',
    (int) 4 => 'dolor',
    (int) 5 => '',
    (int) 6 => 'sit',
    (int) 7 => '',
    (int) 8 => 'amet',
    (int) 9 => ''
]

But when I debug or print the array with all words, the last word is removed from the array, in this case it will be the word "elit". How can I fix this?

Answer 1

You can use (?= |$) as lookahead meaning a word is either followed by a non-word or end of input:

preg_match_all('/([a-z]+)(?=\W|$)/i', $string, $matches);

print_r($matches[0]);

output:

Array
(
    [0] => Lorem
    [1] => ipsum
    [2] => dolor
    [3] => sit
    [4] => amet
    [5] => consectetur
    [6] => adipiscing
    [7] => elit
    [8] => Lorem
    [9] => ipsum
    [10] => dolor
    [11] => sit
    [12] => amet
    [13] => consectetur
    [14] => adipiscing
    [15] => elit
)

btw you can get same using split operation:

$tokens = preg_split('/\h+/', $string);

\\h matches a horizontal whitespace.

Answer 2

Use the following regex pattern to get all the words

\\w matches any word character (letter, number, underscore)

preg_match_all('#\w+#', $string, $words);
print_r($words);

Will output

Array
(
    [0] => Array
        (
            [0] => Lorem
            [1] => ipsum
            [2] => dolor
            [3] => sit
            [4] => amet
            [5] => consectetur
            [6] => adipiscing
            [7] => elit
            [8] => Lorem
            [9] => ipsum
            [10] => dolor
            [11] => sit
            [12] => amet
            [13] => consectetur
            [14] => adipiscing
            [15] => elit
        )

)