Equality Operators
Equality operators (see Table below) , as the name suggest, are used to compare two values, testing for equivalence.
| Example | Label | Outcome |
| $a == $b | Is equal to | True if $a and $b are equivalent |
| $a != $b | Is not equal to | True if $a is not equal to $b |
| $a === $b | Is identical to | True if $a and $b are equivalent and $a and $b have the same type |
Equality Operators
It is a common mistake for even experienced programmers to attempt to test for equality using just one equal sign (e.g., $a = $b). Keep in mind that this will result in the assignment of the contents of $b to $a, thereby not producing the expected results(more about assignment operators). $a = 2 <- this expression assigns 2 to variable $a, whereas, $a == 2 <— this expression checks if value of variable $a is equal to 2 or not, and , hence, returns true or false respectively.
Comparison Operators
Comparison operators (see Table below), like logical operators, provide a method to direct program flow through an examination of the comparative values of two or more variables.
| Example | Label | Outcome |
| $a < $b | Less than | True if $a is less than $b |
| $a > $b | Greater than | True if $a is greater than $b |
| $a <= $b | Less than or equal to | True if $a is less than or equal to $b |
| $a >= $b | Greater than or equal to | True if $a is greater than or equal to $b |
| ($a == 12) ? 5 : -1 | Ternary | If $a equals 12, return value is 5; otherwise, return value is –1 |
Comparison Operators
Note:- The comparison operators should be used only for comparing numerical values. Although you may be tempted to compare strings data types with these operators, you will most likely not arrive at the expected outcome if you do so. There is a substantial set of predefined functions that compare string values we’ll be discussing it in detail later on the go.
Bitwise Operators
Bitwise operators examine and manipulate integer values(more about data types) on the level of individual bits that make up the integer value (thus the name). To fully understand this concept, you need at least an introductory knowledge of the binary representation of decimal integers. Table below presents a few decimal integers and their corresponding binary representations.
| Decimal Integer | Binary Representation |
| 2 | 10 |
| 5 | 101 |
| 10 | 1010 |
| 12 | 1100 |
| 145 | 10010001 |
| 1,452,012 | 101100010011111101100 |
Binary Representations
The bitwise operators listed in Table below are variations of some of the logical operators but can result in drastically different outcomes.
If you are interested in learning more about binary encoding and bitwise operators and why they are important, check out Randall Hyde’s massive online reference, “The Art of Assembly Language Programming”.
| Example | Label | Outcome |
| $a & $b | AND | And together each bit contained in $a and $b |
| $a | $b | OR | Or together each bit contained in $a and $b |
| $a ^ $b | XOR | Exclusive—or together each bit contained in $a and $b |
| ~ $b | NOT | Negate each bit in $b |
| $a << $b | Shift Left | $a will receive the value of $b shifted left two bits |
| $a >> $b | Shift Right | $a will receive the value of $b shifted right two bits |
Bitwise Operators
You have been introduced to operands and various operators namely Arithmetic, Assignment, String, Increment & Decrement, Logical, Equality, Comparison and Bitwise Operators, including there associativity and precedence. For any doubts related to expressions and previous lectures comment below or contact me.
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