I recently discovered this interesting article by Deceze.
But I'm a bit confused by one of its advises:
never use empty or isset for variables that should exist
Using empty() is not good choice to test if $foo = ''; is empty?
5 Answers
You should not use empty (or isset) if you expect $foo to exist. That means, if according to your program logic, $foo should exist at this point:
if ($foo === '')
Then do not do any of these:
if (isset($foo))
if (empty($foo))
These two language constructs suppress error reporting for undefined variables. That's their only job. That means, if you use isset or empty gratuitously, PHP won't tell you about problems in your code. For example:
$foo = $bar;
if (empty($føø)) ...
Hmm, why is this always true, even when $bar contains the expected value? Because you mistyped the variable name and you're checking the value of an undefined variable. Write it like this instead to let PHP help you:
if (!$føø) ...
Notice: undefined variable føø on line ...
The condition itself is the same, == false (!) and empty produce the same outcome for the same values.
How exactly to check for an empty string depends on what values you do or don't accept. Perhaps $foo === '' or strlen($foo) == 0 is the check you're looking for to ensure you have a string with something in it.
Comments
What he means is if you want to check if the string is empty then empty won't do that. Empty can mean false, 0, null. Anything 'falsy'.
E.g. these are all true:
<?php
$string = null;
if (empty($string)) {
echo "This is true";
}
$string = '';
if (empty($string)) {
echo "This is true";
}
$string = 0;
if (empty($string)) {
echo "This is true";
}
If you want to check if the string is an empty string you should do this check for '':
<?php
$string = '';
if (isset($string) && $string === '') {
echo "This is true";
}
$string = null;
if (isset($string) && $string === '') {
echo "This is false";
}
3 Comments
deceze
That's not actually what he means. He means that unless you're unsure whether the variable itself may or may not be set, don't use
empty or isset. In all your examples the variable $string is guaranteed to exist when you're trying to use it, so the isset check (and by extension empty) is completely superfluous. How exactly to check "how empty" your string is is a different topic. strlen would be the best test for that.
Antony Thompson
@deceze answer is much better
Your Common Sense
Not only superfluous but actually harmful. Because isset and empty are just little brothers of @.
PHP's empty() can be used in many cases.
It works for checking:
if a string is
blankif a variable is
undefinedornull
And of course empty() is best for your case too.
3 Comments
ʰᵈˑ
Also if a blank array - plus all those other "falsey" alternatives (
(int) 0, etc).deceze
empty does exactly the same thing as == false, except it doesn't throw any errors if the whole variable you're testing doesn't exist (empty($undefined) → no errors, $undefined == false → Notice: undefined variable).Your Common Sense
On the contrary, anything but "best"
Try using this php if function: $retVal = (condition) ? a : b ;
where condition: $value == null
a: is the value to display if $value is null
b: is the actual value to display or any other value to be displayed when $value is not null
In case of further guidance, kindly comment
Comments
Check String is empty or Not
<?php
$test='';
if(empty($test)){
echo'It is empty';
} else{
echo'Its not empty';
}
?>
1 Comment
Your Common Sense
The accepted answer explicitly explains why you shouldn't
$fooitself may not exist? Unless that's a legitimate possibility you want to account for, don't useempty;== falsewould do the same thing without disabling error reporting.