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5 ways to determine whether an array is empty in PHP
- 巴扎黑Original
- 2016-11-11 09:45:47902browse
In PHP, "NULL" and "empty" are two concepts.
isset is mainly used to determine whether a variable has been initialized.
empty can judge variables with values of "false", "empty", "0", "NULL" and "uninitialized" as TRUE.
is_null can only judge variables with values of " NULL" variables are judged as TRUE
var == null Variables with values "false", "empty", "0", and "NULL" are all judged as TRUE
var === null Only variables with values are "NULL" The variable is judged to be TRUE
Note: When judging whether a variable is really "NULL", is_null is mostly used to avoid interference from "false", "0" and other values.
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