PHP Operators
PHP Operator is a symbol i.e used to perform operations on operands. In simple words, operators are used to perform operations on variables or values. For example:
- $num=10+20;//+ is the operator and 10,20 are operands
In the above example, + is the binary + operator, 10 and 20 are operands and $num is variable.
PHP Operators can be categorized in following forms:
- Arithmetic Operators
- Assignment Operators
- Bitwise Operators
- Comparison Operators
- Incrementing/Decrementing Operators
- Logical Operators
- String Operators
- Array Operators
- Type Operators
- Execution Operators
- Error Control Operators
We can also categorize operators on behalf of operands. They can be categorized in 3 forms:
- Unary Operators: works on single operands such as ++, — etc.
- Binary Operators: works on two operands such as binary +, -, *, / etc.
- Ternary Operators: works on three operands such as “?:”.
Arithmetic Operators
The PHP arithmetic operators are used to perform common arithmetic operations such as addition, subtraction, etc. with numeric values.
| Operator | Name | Example | Explanation |
|---|---|---|---|
| + | Addition | $a + $b | Sum of operands |
| – | Subtraction | $a – $b | Difference of operands |
| * | Multiplication | $a * $b | Product of operands |
| / | Division | $a / $b | Quotient of operands |
| % | Modulus | $a % $b | Remainder of operands |
| ** | Exponentiation | $a ** $b | $a raised to the power $b |
The exponentiation (**) operator has been introduced in PHP 5.6.
Assignment Operators
The assignment operators are used to assign value to different variables. The basic assignment operator is “=”.
| Operator | Name | Example | Explanation |
|---|---|---|---|
| = | Assign | $a = $b | The value of right operand is assigned to the left operand. |
| += | Add then Assign | $a += $b | Addition same as $a = $a + $b |
| -= | Subtract then Assign | $a -= $b | Subtraction same as $a = $a – $b |
| *= | Multiply then Assign | $a *= $b | Multiplication same as $a = $a * $b |
| /= | Divide then Assign (quotient) |
$a /= $b | Find quotient same as $a = $a / $b |
| %= | Divide then Assign (remainder) |
$a %= $b | Find remainder same as $a = $a % $b |
Bitwise Operators
The bitwise operators are used to perform bit-level operations on operands. These operators allow the evaluation and manipulation of specific bits within the integer.
| Operator | Name | Example | Explanation |
|---|---|---|---|
| & | And | $a & $b | Bits that are 1 in both $a and $b are set to 1, otherwise 0. |
| | | Or (Inclusive or) | $a | $b | Bits that are 1 in either $a or $b are set to 1 |
| ^ | Xor (Exclusive or) | $a ^ $b | Bits that are 1 in either $a or $b are set to 0. |
| ~ | Not | ~$a | Bits that are 1 set to 0 and bits that are 0 are set to 1 |
| << | Shift left | $a << $b | Left shift the bits of operand $a $b steps |
| >> | Shift right | $a >> $b | Right shift the bits of $a operand by $b number of places |
Comparison Operators
Comparison operators allow comparing two values, such as number or string. Below the list of comparison operators are given:
| Operator | Name | Example | Explanation |
|---|---|---|---|
| == | Equal | $a == $b | Return TRUE if $a is equal to $b |
| === | Identical | $a === $b | Return TRUE if $a is equal to $b, and they are of same data type |
| !== | Not identical | $a !== $b | Return TRUE if $a is not equal to $b, and they are not of same data type |
| != | Not equal | $a != $b | Return TRUE if $a is not equal to $b |
| <> | Not equal | $a <> $b | Return TRUE if $a is not equal to $b |
| < | Less than | $a < $b | Return TRUE if $a is less than $b |
| > | Greater than | $a > $b | Return TRUE if $a is greater than $b |
| <= | Less than or equal to | $a <= $b | Return TRUE if $a is less than or equal $b |
| >= | Greater than or equal to | $a >= $b | Return TRUE if $a is greater than or equal $b |
| <=> | Spaceship | $a <=>$b | Return -1 if $a is less than $b Return 0 if $a is equal $b Return 1 if $a is greater than $b |
Incrementing/Decrementing Operators
The increment and decrement operators are used to increase and decrease the value of a variable.
| Operator | Name | Example | Explanation |
|---|---|---|---|
| ++ | Increment | ++$a | Increment the value of $a by one, then return $a |
| $a++ | Return $a, then increment the value of $a by one | ||
| — | decrement | –$a | Decrement the value of $a by one, then return $a |
| $a– | Return $a, then decrement the value of $a by one |
Logical Operators
The logical operators are used to perform bit-level operations on operands. These operators allow the evaluation and manipulation of specific bits within the integer.
| Operator | Name | Example | Explanation |
|---|---|---|---|
| and | And | $a and $b | Return TRUE if both $a and $b are true |
| Or | Or | $a or $b | Return TRUE if either $a or $b is true |
| xor | Xor | $a xor $b | Return TRUE if either $ or $b is true but not both |
| ! | Not | ! $a | Return TRUE if $a is not true |
| && | And | $a && $b | Return TRUE if either $a and $b are true |
| || | Or | $a || $b | Return TRUE if either $a or $b is true |
String Operators
The string operators are used to perform the operation on strings. There are two string operators in PHP, which are given below:
| Operator | Name | Example | Explanation |
|---|---|---|---|
| . | Concatenation | $a . $b | Concatenate both $a and $b |
| .= | Concatenation and Assignment | $a .= $b | First concatenate $a and $b, then assign the concatenated string to $a, e.g. $a = $a . $b |
Array Operators
The array operators are used in case of array. Basically, these operators are used to compare the values of arrays.
| Operator | Name | Example | Explanation |
|---|---|---|---|
| + | Union | $a + $y | Union of $a and $b |
| == | Equality | $a == $b | Return TRUE if $a and $b have same key/value pair |
| != | Inequality | $a != $b | Return TRUE if $a is not equal to $b |
| === | Identity | $a === $b | Return TRUE if $a and $b have same key/value pair of same type in same order |
| !== | Non-Identity | $a !== $b | Return TRUE if $a is not identical to $b |
| <> | Inequality | $a <> $b | Return TRUE if $a is not equal to $b |
Execution Operators
PHP has an execution operator backticks (“). PHP executes the content of backticks as a shell command. Execution operator and shell_exec() give the same result.
| Operator | Name | Example | Explanation |
|---|---|---|---|
| “ | backticks | echo `dir`; | Execute the shell command and return the result. Here, it will show the directories available in current folder. |
Note: Note that backticks (“) are not single-quotes.
Error Control Operators
PHP has one error control operator, i.e., at (@) symbol. Whenever it is used with an expression, any error message will be ignored that might be generated by that expression.
| Operator | Name | Example | Explanation |
|---|---|---|---|
| @ | at | @file (‘non_existent_file’) | Intentional file error |
PHP Operators Precedence
Let’s see the precedence of PHP operators with associativity.
| Operators | Additional Information | Associativity |
|---|---|---|
| clone new | clone and new | non-associative |
| [ | array() | left |
| ** | arithmetic | right |
| ++ — ~ (int) (float) (string) (array) (object) (bool) @ | increment/decrement and types | right |
| instanceof | types | non-associative |
| ! | logical (negation) | right |
| * / % | arithmetic | left |
| + – . | arithmetic and string concatenation | left |
| << >> | bitwise (shift) | left |
| < <= > >= | comparison | non-associative |
| == != === !== <> | comparison | non-associative |
| & | bitwise AND | left |
| ^ | bitwise XOR | left |
| | | bitwise OR | left |
| && | logical AND | left |
| || | logical OR | left |
| ?: | ternary | left |
| = += -= *= **= /= .= %= &= |= ^= <<= >>= => | assignment | right |
| and | logical | left |
| xor | logical | left |
| or | logical | left |
| , | many uses (comma) | left |
