Here is a summary of PHP operators
【List】
① Arithmetic operators;
② assignment operator;
③ string operator;
④ Increment/decrement operator;
⑤Comparison operator;
⑥ Logical operators;
⑦Array operator;
【Details】
① Arithmetic operators: +, -, *, /, % (addition, subtraction, multiplication and division remainder)
②Assignment operator: The PHP assignment operator is used to write values to variables. The basic assignment operator is "=", which means that the assignment expression on the right will set the value of the operand on the left. List:
x = y x = y
x += y x = x + y
x -= y x = x - y
x *= y x = x * y
x /= y x = x / y
x %= y x = x % y
③ String operators: concatenation, concatenation assignment
| . | tandem | $txt1 = "Hello" $txt2 = $txt1 . " world!" | $txt2 now contains "Hello world!" |
| .= | concatenation assignment | $txt1 = "Hello" $txt1 .= " world!" | $txt1 now contains "Hello world!" |
Case:
<?php $a = "Hello"; $b = $a . "world!";//Concatenation echo $b; // print Hello world! $x="Hello"; $x .= "world!";//Concatenate assignment 1 echo $x; // output Hello world! ?>
④ Increment/Decrement operator
| ++$x | pre-increment | Increment $x by one, then return $x |
| $x++ | post increment | Returns $x, then increments $x by one |
| --$x | pre-decrement | Decrement $x by one, then return $x |
| $x-- | post decrement | Return $x, then decrement $x by one |
Case:
<?php $x=10; echo ++$x; // output 11 $y=10; echo $y++; // output 10 $ z = 5; echo --$z; // output 4 $i=5; echo $i--; // output 5 ?>
⑤Comparison operator
== equals $x == $y Returns true if $x equals $y.
=== Congruent (identical) $x === $y Returns true if $x is equal to $y and they are of the same type.
!= not equal to $x != $y Returns true if $x is not equal to $y.
<> not equal to $x <> $y Returns true if $x is not equal to $y.
!== not congruent (completely different) $x !== $y Returns true if $x is not equal to $y, or if they are not of the same type
> greater than $x > $y Returns true if $x is greater than $y.
< less than $x < $y Returns true if $x is less than $y.
>= greater than or equal to $x >= $y Returns true if $x is greater than or equal to $y.
<= less than or equal to $x <= $y Returns true if $x is less than or equal to $y.
⑥ Logical operators
and 与 $x and $y
or 或 $x or $y
xor XOR $x xor $y
&& 与 $x && $y
|| or $x || $y
! not !$x
⑦Array operator
Array operators are used to compare arrays
+ union of $x and $y (but not covering duplicate keys)
== equal Returns true if $x and $y have the same key/value pair.
=== Congruent Returns true if $x and $y have the same key/value pair, same order, same type.
!= not equal Returns true if $x is not equal to $y.
<> not equal Returns true if $x is not equal to $y.
!== Not Congruent Returns true if $x and $y are completely different.
Example:
<?php
$x = array("a" => "red", "b" => "green");
$y = array("c" => "blue", "d" => "yellow");
$z = $x + $y; // union of $x and $y
var_dump($z);
var_dump($x == $y);
var_dump($x === $y);
var_dump($x != $y);
var_dump($x <> $y);
var_dump($x !== $y);
?>
.