`isset() vs. !empty(): When Is One Redundant?`

Understanding the Difference between isset() and !empty()

The use of both isset() and !empty() in the same condition, as in isset($vars[1]) AND !empty($vars[1]), is redundant. To understand why, it's essential to distinguish between these two functions:

isset()

• Checks if a variable is set or declared.
• Returns true if the variable exists, even if its value is null.
• If the variable is undefined, isset() throws a warning.

!empty()

• Checks if a variable is not empty.
• Equivalent to !isset($foo) || !$foo.
• Returns true if the variable is set and not empty, and false otherwise.
• Unlike isset(), !empty() does not throw warnings if the variable is not set.

Therefore, the condition isset($vars[1]) AND !empty($vars[1]) is redundant because:

• !empty($vars[1]) already checks if the variable is set.
• isset($vars[1]) is unnecessary since it checks for a condition that is already fulfilled by !empty().

Shorter Alternative

To check if a variable is set and not empty, you can simply use:

!empty($vars[1])

This expression combines the functionality of both isset() and !empty() without the redundancy.

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