Home / Questions / 34946
Accepted
Diablo
Asked: 2020-11-21 15:58:17 +0800 CST 2020-11-21 15:58:17 +0800 CST

How to check if a string contains a specific word in PHP?

  • 772

We consider that the variable $foocontains a string with value hello world . My question is: how could one check if it $foocontains the word world and throw a echo?

$foo = 'Hola mundo';

if($foo contiene 'mundo') {
  echo 'True';
}
php

5 Answers

  1. Best Answer

    You can do this with the function strpos, which allows you to find the position of the first occurrence of a substring in a string, that is, the position of the first occurrence of a string within another string.

    If the position is not found, it will return false.

    $foo = 'Hola mundo';

if (strpos($foo, 'mundo') !== false) {
    echo 'true';
}
    • 22

  2. Error404's answer is the best (use strpos, striposor strstr), as an alternative I'm going to suggest using regular expressions and preg_matchthat it can be useful in other cases (for example if you need to search for some pattern more than a specific string) and that, although it will work in your case particular, is not recommended because it will be slower.

    So you could do something like:

    $foo = 'Hola mundo'; 

if(preg_match('/mundo/i', $foo)){
    echo 'True';
}
    • 5

  3. Another option would be to use the function strstr(String string,String search) finds the first occurrence of a string within another string , If it finds the value sought, it will be that the value returned, otherwise it will return an empty string. To all this applying the function strlen(String string) to obtain the length of the string (if it is greater than 0 it is found)

    $foo = 'Hola mundo';
if (strlen(strstr($foo,'mundo'))>0) {
  echo "Se encuentra";
}

    The above function is case sensitive, if you want it to not matter, use the function stristr(String string,String search)

    $foo = 'Hola mundo';
if (strlen(stristr($foo,'MUNDO'))>0) {
  echo "Se encuentra";
}
    • 5

  4. The stripos, strposand functions strstrare used to find substrings .
    For example, they would find the word "la"inside "hola mundo".

    If you are looking for words , you must check that there are no alphanumeric characters before and after the word. Using regular expressions, the assertion \bmatches at these positions.

    function contiene_palabra($texto, $palabra){
    return preg_match('*\b' . $palabra . '\b*i', $texto);
}

    Demo: http://ideone.com/W8OJG5


    Just be aware that $palabrait shouldn't have any of the following regex metacharacters, and might fail if it did.

     \   ^   $   .   |   ?   *   +   (   )   [   {

    This is a secure version:

    function contiene_palabra($texto, $palabra){
    return preg_match('*\b' . preg_quote($palabra) . '\b*i', $texto);
}


    And, to know in which position the word is found:

    function contiene_palabra($texto, $palabra){
    if (preg_match('*\b' . preg_quote($palabra) . '\b*i', $texto, $matches, PREG_OFFSET_CAPTURE)){
        return $matches[0][1];
    }
    return -1;  // -1 cuando no se encuentra
}

    if (($pos = contiene_palabra($texto,$palabra)) >= 0) {
    echo "'$texto' contiene la palabra '$palabra' en la posición $pos.\n";
} else {
    echo "No se encuentra la palabra '$palabra' en '$texto'.\n";
}

    Demo: http://ideone.com/7Jh4nX

    • 5

  5. Update 2022 and PHP 8.

    Another alternative is to use str_contains() (PHP 8.0+). See specification .

    > $foo = 'Hola mundo';
> var_dump(str_contains($foo, 'mundo'));
true

    You can work directly with multibyte , so version is not needed mb_*

    > $var = 'La casa tiene baño y jardín atrás';
> var_dump(str_contains($var, 'baño y jardín'));
true

    It is case sensitive , so do the previous conversions if necessary.

    > var_dump(str_contains($var, 'Casa'));
false
    • 1