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This article mainly introduces the relevant knowledge of "what is the meaning of empty in php". The editor shows you the operation process through an actual case. The operation method is simple, fast and practical. I hope this article "what is the meaning of empty in php" can help you solve the problem.

In PHP, empty means empty, is a built-in function, used to check whether a variable is empty, the syntax is "empty (mixed $var)"; when the variable does not exist or the value of the variable is used for false, the variable is judged to be nonexistent, and the empty () function does not generate a warning.

This article operating environment: Windows10 system, PHP7.1 version, Dell G3 computer.

Empty in php

Empty means null, which is a built-in function in php to check whether a variable is empty.

Empty () determines whether a variable is considered empty. When a variable does not exist, or when its value is equal to FALSE, then it is considered nonexistent. Empty () does not generate a warning if the variable does not exist.

Grammar

Bool empty (mixed $var)

Parameter description:

Var: the variable to be checked.

Note: prior to PHP 5.5, empty () only supported variables; anything else would cause a parsing error. In other words, the following code will not take effect:

Empty (trim ($name))

Instead, you should use:

Trim ($name) = = false

Empty () does not generate a warning, even if the variable does not exist. This means that empty () is essentially equivalent to! isset ($var) | | $var = = false.

Return value

Returns FALSE if var exists and is a non-empty non-zero value. Otherwise, TRUE is returned.

The following variables are considered empty:

"" (empty string)

0 (0 as an integer)

0.0 (as 0 of a floating point number)

"0" (as 0 of the string)

NULL

FALSE

Array () (an empty array)

$var; (a variable that is declared but has no value)

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