Comparing PHP functions: empty(), is_null(), isset().

It seems like there might be a few typos in your question, but I'll assume you're asking about comparing three PHP functions: empty(), is_null(), and isset(). These functions are used to check the status and value of variables in PHP. Let's discuss each function and their differences:

In summary:

• Use empty() to check if a variable is considered empty, including null.

$var1 = "";      // Empty string  // empty($var1) => true
$var1 = "0";     // Empty string  // empty($var1) => true
$var2 = null;    // Null value    //  empty($var2) => true
$var3 = 0;       // Numeric zero  // empty($var3) => true
$var4 = array(); // Empty array   // empty($var4) => true

• Use is_null() to specifically check if a variable is null.

$var = null;  // is_null($var) => true
$var = 0;  // is_null($var) => false
$var = array();  // is_null($var) => false

• Use isset() to check if a variable is set and not null.

$var = null; // isset($var) => false
$var = "Hello"; // isset($var) => true
$var = 0;      // isset($var) => true
$var = array();  // isset($var) => true

Comments

[Given Ncube]

Thanks for clearing the confusion Johnny
I personally prefer to use empty() to check if an array or any iterable type has any elements in it

is_null() to check if a varaible is null. I rarely use isset() but comes very handy when checking a variable has been declared

[JohnDivam]

Thank you Given Ncube! !
I'm glad you found it helpful.

[Edenn Touitou]

You can also add in your examples :

$var5 = false; //empty($var5) => true

[Allester Corton]

Clearly

[Shshank]

Nice post it will help other dev who faced confusion between empty and isset.

[JohnDivam]

Thank you Shshank!