is_string

(PHP 4, PHP 5)

is_string — Find whether the type of a variable is string

Opis

bool is_string ( mixed $var )

Finds whether the type given variable is string.

Parametry

var: The variable being evaluated.

Zwracane wartości

Returns TRUE if var is of type string, FALSE otherwise.

Przykłady

Przykład #1 is_string() example


<?php
if (is_string("23")) {
    echo "is string\n";
} else {
    echo "is not a string\n";
}
var_dump(is_string('abc'));
var_dump(is_string("23"));
var_dump(is_string(23.5));
var_dump(is_string(true));
?>

Powyższy przykład wyświetli:

is string
bool(true)
bool(true)
bool(false)
bool(false)

Zobacz też:

is_float() - Finds whether the type of a variable is float
is_int() - Find whether the type of a variable is integer
is_bool() - Finds out whether a variable is a boolean
is_object() - Finds whether a variable is an object
is_array() - Finds whether a variable is an array

add a note User Contributed Notes is_string

slicky at newshelix dot com 20-Mar-2001 05:06


Be aware that this function could result into unwanted results if you check single chars in an array.


For instance:


You have a simple string and want to repeat this string evertime it ends.





<?php


for ($i=0; $i < strlen($string);$i++){


    if(!is_string($key[$x]))


        $x = 0;


    echo $key[$x];


    $x++;


}


?>





This will print you out the key, but won't iterate it since $x won't be reset. is_string function will give out true at element in that string, even if it doesn't exist. for instance is_string $key[1000] while your string is just 10chars long.


However this doesn't matter just use $key[$x] == '' instead.


Of course you won't use this to iterate a string, but you might come across something where this get useful, for instance for a en/decrypt engine.

add a note