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[edit] Last updated: Fri, 10 Feb 2012

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is_string

(PHP 4, PHP 5)

is_stringFind whether the type of a variable is string

Description

bool is_string ( mixed $var )

Finds whether the type given variable is string.

Parameters

var

The variable being evaluated.

Return Values

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

Examples

Example #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));
?>

The above example will output:

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

See Also

  • 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 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.

 
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