PHP Mobile Internet Development Notes (3)?? Operator

First, the PHP operator

PHP has a rich set of operators, most of which come directly from the C language. Depending on the function, operators can be divided into: arithmetic operators, string operators, assignment operators, bitwise operators, conditional operators, and logical operators. When the various operators are in the same expression, their operations have a certain precedence.

(1) Arithmetic operations

+ - * / % ++ --

(2) String operators

There is only one string operator. (dot) is the end of the English period. It can concatenate strings together, form new strings, or concatenate strings to numbers, and the type will automatically convert.

View Source

Print?

1. $a = "Dawanganban";

2. $b = "123";

3. Echo $a. $b; Output Result: dawanganban123

(3) Assignment operator

View Source

Print?

01. = + = = *=/=%=. =

02.

03.

04.

$a = "Dawanganban";

. $a. =1;

. $a. =2;

$a. =3;

$a. Echo $b; Output Result: dawanganban123

(4) Bitwise operator

& | ~ ^ << >>

(5) Comparison operators

> < >= <= = = = = <> = = =!==

<>: Not equal to and! = Same

= = =: Identical, values equal and type consistent

！ = =: Non-identical, value not equal or type inconsistent

1. View Source

   Print?

   1. Echo 5 = = "5"; True PHP is a weakly typed language (the variables in JS are similar)

   2. echo 5 = = = "5"; False is exactly equal to

(6) Logical operation

and (Logical AND) or (logical OR) XOR (logical XOR) && (logic and) | | (Logical OR)! (Logical non)

View Source

Print?

1. Var_dump (5 && ""); False

2. Var_dump (5 && "2"); True

3. Var_dump (5 | | ""); True

4. Var_dump (0 xor 1); True

5. Var_dump (0 xor 0); False

6. Var_dump (1 xor 1); False

