What is the difference between isset() and empty() in php

The difference between isset() and empty() in php is: isset() function is used to detect whether the variable is set, the syntax format is: [isset (mixed var)]; empty() function is used to determine the value Whether it is empty, the syntax format is: [empty(mixed var)].

isset() function

isset() function is generally used to detect whether a variable is set.

Format:

bool isset ( mixed var [, mixed var [, ...]] )

Return value:

If the variable does not exist, it returns FALSE;

If the variable exists and its value is NULL, it also returns FALSE ;

If the variable exists and the value is not NULL, TRUE is returned;

When multiple variables are checked at the same time, TRUE is returned only when each single item meets the previous requirement, otherwise the result is FALSE .

empty() function

empty() function is used to determine whether the value is empty.

Format:

bool empty ( mixed var )

Return value:

If the variable does not exist, it returns TRUE;

If the variable exists and its value is "", 0, "0", NULL,, FALSE, array(), var $var; and objects without any attributes, return TRUE;

If the variable exists and the value is not "", 0, "0", NULL, FALSE, array(), var $var; and objects without any attributes, return FALSE.

Example: Simple comparison of empty() and isset()

Note: empty() only detects variables, and detecting anything that is not a variable will cause a parsing error.

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