Logical operators in php include not equal to, or, and, and not (the priority is: ! > && > || > and > xor > or). Let me introduce to you the logical operations in php. How to use the symbol.
Note:
The priority is: ! > && > || > and > xor > or
Also note that although ! has higher precedence than =, PHP still allows expressions like the following: if (!$a = foo()), in this case the output of foo() is assigned to $a .
First look at the manual and I agree with a sentence in the manual: using brackets can enhance the readability of the code.
例子 | 名称 | 结果 |
---|---|---|
$a and $b | And(逻辑与) | TRUE,如果 $a 与 $b 都为 TRUE。 |
$a or $b | Or(逻辑或) | TRUE,如果 $a 或 $b 任一为 TRUE。 |
$a xor $b | Xor(逻辑异或) | TRUE,如果 $a 或 $b 任一为 TRUE,但不同时是。 |
! $a | Not(逻辑非) | TRUE,如果 $a 不为 TRUE。 |
$a && $b | And(逻辑与) | TRUE,如果 $a 与 $b 都为 TRUE。 |
$a || $b | Or(逻辑或) | TRUE,如果 $a 或 $b 任一为 TRUE。 |
In php, "|" is a php bit operator, and "||" is a logical operator
Bitwise operator code:
The code is as follows
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Copy code
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||||
代码如下 | 复制代码 | ||||
$a=0; $b=0; if($a=3 || $b=3){ $a++; $b++; } echo $a.','.$b; //输出 1,1 ?> |
$b=0;
if($a=3 | $b=3){
$a++;
$b++;
The code is as follows | Copy code |
$a=0;<🎜> $b=0;<🎜> if($a=3 || $b=3){<🎜> $a++;<🎜> $b++;<🎜> }<🎜> echo $a.','.$b; //Output 1,1<🎜> ?> In the above two examples, in the first example, "$a=3 | $b=3", since the priority of "|" is higher than the assignment operator, the order of operations can be written as "$a =(3 | $b=3)", first $b is assigned the value 3, and $a is assigned the value of the binary number 0100 | 0100, which is still 0100, so $a is assigned the value 0100 at this time, which is decimal 3. The assignment is successful, true is returned, and the content in the if code block is executed. $a is incremented, and $b is also incremented. Therefore, $a=4, $b=4 In the second example, it can also be seen as "$a = (3 || $b = 3)". First, 3||$b=3 returns true, "||" causes a short circuit, and the "||" before 3 is already true, "$b=3" is no longer executed, so $b is still 0 at this time, $a is true of Boolean type, the assignment is successful, true is returned, the content in the if code block is executed, and $a++ returns is true, $b++ is 1, so, $a=1,$b=1 |