PHP Operators Tutorial

What are operators?

Operators are symbols that have special meaning in PHP, and they indicate the types of operations that can be done.

As an example, we can consider the + symbol as an operator. It adds whatever number is on the right to the number on the left. This is an operation that is taking place on two operands.

PHP categorizes operators into different types:

1. Array operators
2. Arithmetic operators
3. Assignment operators
4. Conditional assignment operators
5. Comparison operators
6. Incremental operators
7. Logical operators
8. String operators

Array operators

Array operators are used to compare arrays. The array operators below may not make any sense at this point, if you are a beginner. We will cover these operators again in the tutorial lesson on arrays.

The following table lists array operators in PHP.

Arithmetic operators

Arithmetic operators are used with numerical values to perform common mathematical arithmetic.

The following table lists arithmetic operators in PHP.

<?php

$br = "<br>";
$a = 3;
$b = 4;

// Addition
echo $a + $b;
echo $br;

// Subtraction
echo $b - $a;
echo $br;

// Multiplicaion
echo $a * $b;
echo $br;

// Division
echo $b / $a;
echo $br;

// Modulus
echo $b % $a;
echo $br;

// Exponent
echo $b ** $a;
echo $br;

?>

Assignment operators

Assignment operators are used with numerical values to assign a value to a variable.

The following table lists assignment operators in PHP.

<?php

// Assignment
$br = "<br>";
$a = 3;

// Addition Assignment
echo $a += 10;
echo $br;

// Subtraction Assignment
echo $a -= 2;
echo $br;

// Multiplicaion Assignment
echo $a *= 5;
echo $br;

// Division Assignment
echo $a /= 1;
echo $br;

// Modulus Assignment
echo $a %= 1;
echo $br;

?>

Conditional assignment operators

Conditional assignment operators will set values depending on the outcome of certain conditions. The conditional operators below may not make any sense at this point, if you are a beginner. We will cover them again in the tutorial lesson on conditional control flow.

The following table lists conditional assignment operators in PHP.

The null coalescing operator is not available in versions below PHP v7.

Comparison operators

Comparison operators will compare two values against each other and return a true or false boolean value.

The following table lists comparison operators in PHP.

It is important for programmers coming from Javascript to remember that three equal signs === represents evaluating both equal value and equal type, and not just equal value.

<?php

$br = "<br>";

// Equal
echo 5 == 5;
echo $br;

// Identical
echo "A" === "A";
echo $br;

// Not equal
echo 3 != 4;
echo $br;

// Not identical
echo 3 !== "Three";
echo $br;

// Greater than
echo 100 > 99;
echo $br;

// Less than
echo 30 < 40;
echo $br;

// Greater than or equal to
echo 2 >= 2;
echo $br;

// Less than or equal to
echo 6 <= 6;
echo $br;

?>

Incremental operators

Incremental operators are used to increase a value incrementally, and decremental operators are used to decrease a value. These operators are what is known as unary operators and as such only require one operand.

The following table lists incremental and decremental operators in PHP.

<?php

$br = "<br>";
$a = 1;

echo $a;
echo $br;

// Increment and return value
echo ++$a;
echo $br;

// Return value, then increment
echo $a++;
echo $br;
echo $a;
echo $br;

// Decrement and return value
echo --$a;
echo $br;

// Return the value, then decrement
echo $a--;
echo $br;
echo $a;

?>

In the example above we can see that in both pre and post increments the value is incremented. The choice of which to use is determined by which value we want to work with:

• If we want to work with the already incremented value, we choose the pre-increment.
• If we want to work with the value before it is incremented and increment it afterwards, we choose the post-increment.

In most situations it won’t matter because we only want the value to actually increment, and not specifically use the value. We will look into increments and decrements more in the tutorial lesson on looping control flow.

Logical operators

Logical operators are used to combine conditional evaluations. We will work with them again in the tutorial lesson on conditional control flow.

The following table lists logical operators in PHP.

<?php

$br = "<br>";

// And
echo 1 == 1 and 2 == 2;
echo $br;

// Or
echo 1 == 1 or 2 == 2;
echo $br;

// Xor
echo 1 == 2 or 2 == 2;
echo $br;

// && (and)
echo 1 == 1 and 2 == 2;
echo $br;

// || (or)
echo 1 == 1 or 2 == 2;
echo $br;

// ! (not)
echo !false;

?>

String operators

String operators are operators that combine (concatenate) strings together.

The following table lists string operators in PHP.

<?php

$br = "<br>";
$str1 = "Hello";
$str2 = "there";

// Concatenation
echo $str1 . " " . $str2;
echo $br;

// Append
echo $str1 .= $str2;

?>

Summary: Points to remember

• Operators are like keywords that have special meaning in PHP, and indicate operations that can be done.
• The null coalescing operator ? ? is not available in versions below PHP 7.
• Javascript programmers should note that === means evaluating both equal value and equal type, and not only equal value.
• These operators will be used more throughout the tutorial series, and will become much clearer for you.