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

Answer 1

I just write my own function, is_string for type checking and strlen to check the length.

function emptyStr($str) {
    return is_string($str) && strlen($str) === 0;
}

print emptyStr('') ? "empty" : "not empty";
// empty

Here's a small test repl.it

EDIT: You can also use the trim function to test if the string is also blank.

is_string($str) && strlen(trim($str)) === 0;    

Answer 2

PHP have a built in function called empty() the test is done by typing if(empty($string)){...} Reference php.net : php empty

Answer 3

You got an answer but in your case you can use

return empty($input);

or

return is_string($input);

Answer 4

Well here is the short method to check whether the string is empty or not.

$input; //Assuming to be the string


if(strlen($input)==0){
return false;//if the string is empty
}
else{
return true; //if the string is not empty
}

Answer 5

if you have a field namely serial_number and want to check empty then

$serial_number = trim($_POST[serial_number]);
$q="select * from product where user_id='$_SESSION[id]'";
$rs=mysql_query($q);
while($row=mysql_fetch_assoc($rs)){
if(empty($_POST['irons'])){
$irons=$row['product1'];
}

in this way you can chek all the fileds in the loop with another empty function

Answer 6

Simple problem actually. Change:

if (strTemp != '')

to

if ($strTemp != '')

Arguably you may also want to change it to:

if ($strTemp !== '')

since != '' will return true if you pass is numeric 0 and a few other cases due to PHP's automatic type conversion.

You should not use the built-in empty() function for this; see comments and the PHP type comparison tables.