The difference between isset and empty in php

isset and empty are PHP functions that check if a variable is set or empty. isset checks for the presence of a variable, regardless of whether its value is null, 0, or the empty string, while empty specifically checks whether the variable is empty, including null, 0, and the empty string.

The difference between isset vs. empty in PHP

isset and empty are used in PHP to check whether a variable Two functions to set or empty. Although these two functions may seem similar, there are some key differences between them.

isset

isset() function checks whether a variable has been set, regardless of whether its value is null, 0, or an empty string. It returns true as long as the variable exists.

empty

empty() function checks whether a variable is empty. It treats the following values ​​as true:

• null
• false
• 0
• Empty string ("")
• Empty array ([])

Difference

The following table summarizes the key differences between isset() and empty() functions:

##true

Features	isset	empty
Check if the variable exists	Yes	No
Return true for null value	No	Yes
Returns	true for the number 0	true
Returns	true# for the empty string

Example

$var = null;

var_dump(isset($var)); // false
var_dump(empty($var)); // true

In the above example, the variable $var is set to null. The isset() function returns false because the variable is not set. The empty() function returns true because the variable is empty.

Summary

Use the isset() function to check whether a variable exists regardless of its value.
• Use the empty() function to check whether the variable is empty, including null, 0 and empty string.

The above is the detailed content of The difference between isset and empty in php. For more information, please follow other related articles on the PHP Chinese website!