Why a function checking if a string is empty always returns true? [closed]

Answer 1

In your if clause in the function, you're referring to a variable strTemp that doesn't exist. $strTemp does exist, though.

But PHP already has an empty() function available; why make your own?

if (empty($str))
    /* String is empty */
else
    /* Not empty */

From php.net:

Return Values

Returns FALSE if var has a non-empty and non-zero value.

The following things are considered to be empty:

* "" (an empty string)
* 0 (0 as an integer)
* "0" (0 as a string)
* NULL
* FALSE
* array() (an empty array)
* var $var; (a variable declared, but without a value in a class)

http://www.php.net/empty

Answer 2

Just use strlen() function

if (strlen($s)) {
   // not empty
}

Answer 3

I needed to test for an empty field in PHP and used

ctype_space($tempVariable)

which worked well for me.

Answer 4

I always use a regular expression for checking for an empty string, dating back to CGI/Perl days, and also with Javascript, so why not with PHP as well, e.g. (albeit untested)

return preg_match('/\S/', $input);

Where \S represents any non-whitespace character

Answer 5

PHP evaluates an empty string to false, so you can simply use:

if (trim($userinput['phoneNumber'])) {
  // validate the phone number
} else {
  echo "Phone number not entered<br/>";
}

Answer 6

You can simply cast to bool, dont forget to handle zero.

function isEmpty(string $string): bool {
    if($string === '0') {
        return false;
    }
    return !(bool)$string;
}

var_dump(isEmpty('')); // bool(true)
var_dump(isEmpty('foo')); // bool(false)
var_dump(isEmpty('0')); // bool(false)