This is mainly related to php non-type languages, such as NULL, FALSE, array (), "", 0, "0 & Prime; if they are equal, but if you determine the true return value of a value, you can use =
$ A = 0;
$ B = FALSE;
$ A = FALSE is not true, but $ B = FALSE is true. If yes, $ a = FALSE and $ B = FALSE are both true.
The ===operator is still very useful. Some built-in functions in php return a value if they succeed, and false if they fail, if it succeeds but the return value is a null value such as "" or 0, how do you determine the success or failure? You can use = to distinguish variable types.
|$ A = $ B||Equal||TRUEIf $ a is equal to $ B.|
|$ A ===$ B||Full||TRUEIf $ a is equal to $ B, and their types are the same. (Introduced in PHP 4)|
|$! = $ B||Not supported||TRUEIf $ a is not equal to $ B.|
|$ A <> $ B||Not supported||TRUEIf $ a is not equal to $ B.|
|$! ==$ B||Incomplete||TRUEIf $ a is not equal to $ B, or they are of different types. (Introduced in PHP 4)|
|$ A <$ B||Xiaohe||TRUEIf $ a is strictly less than $ B.|
|$ A> $ B||Greater||TRUEIf $ a is strict with $ B.|
|$ A <= $ B||Less than or equal||TRUEIf $ a is less than or equal to $ B.|
|$ A> = $ B||Greater than or equal||TRUEIf $ a is greater than or equal to $ B.|
If you compare an integer with a string, the string is converted to an integer. Compare two numeric strings as integers. This rule also applies to switch statements.
|The code is as follows:||Copy code|
Var_dump (0 = "a"); // 0 = 0-> true
Var_dump ("1" = "01"); // 1 = 1-> true
Var_dump ("1" = "1e0"); // 1 = 1-> true
Echo "0 ";
Case "a": // never reached because "a" is already matched with 0