Perl

Perl

A perl operator is a series of symbols used as syntax. An operator is a sort of function and its operands are arguments.

Perl precedence acts like BODMAS in Mathematics. Addition and Subtraction always comes after the Multiplication and Division.

For example,

8 + 4 - 5 * 6 / 3 = 2

Here, answer will be 2 with BODMAS rule. (6 / 3 = 2) will be calculated first, then the quotient 2 will be multiplied by the 5, followed by subtraction and addition.

Example

snippet

use 5.010; use strict; use warnings; my $result1 = 8 + 4 - 5 * 6 / 3 ; say $result1; my $result2 = 12 * 3 + 2 ** 2 << 1; say $result2;

Output

2
80

Operators | Description |
---|---|

++, -- | Auto-increment, Auto-decrement |

-, ~, ! | Operators having one operand |

** | Exponentiation |

=~, !~ | Pattern matching operators |

*, /, %, x | Multiplication, Divisor, Remainder, Repetition |

+, -, . | Addition, Subtraction, Concatenation |

<<, >> | Shifting operators |

-e, -r | File status operators |

<, <=, >, >=, lt, le, gt, ge | Inequality comparison operators |

==, !=, <=>, eq, nq, cmp | Equality comparison operators |

& | Bitwise AND |

|, ^ | Bitwise OR and XOR |

&& | Logical AND |

|| | Logical OR |

. . | List range operators |

? and : | Conditional operators |

=, +=, -=, *= | Assignment operators |

, | Comma operator |

not | low precedence logical NOT |

and | low precedence logical AND |

or, xor | low precedence logical OR and XOR |

The associativity of an operator helps you to decide whether to evaluate an equation from (left to right) or (right to left).

The order of operation is very important. Sometimes it is same from both the sides but sometimes it produces drastic difference.

For example,

7 + 4 + 2 = 13

The answer for this question is same in any order either from left or right.

3 ∗∗ 2 ∗∗ 3

The answer for this question will be (9 ∗∗ 3) from left and (3 ∗∗ 8) from right. Both the answers have a lot of difference.

Example

snippet

use 5.010; use strict; use warnings; my $result = 3 ** 2 ** 3; say $result;

Output

6561

Operators | Description |
---|---|

++, -- | Order of direction is not applicable here |

-, ~, ! | Right-to-Left |

** | Right-to-Left |

=~, !~ | Left-to-Right |

*, /, %, x | Left-to-Right |

+, -, . | Left-to-Right |

<<, >> | Left-to-Right |

-e, -r | Order of direction is not applicable here |

<, <=, >, >=, lt, le, gt, ge | Left-to-Right |

==, !=, <=>, eq, ne, cmp | Left-to-Right |

& | Left-to-Right |

|, ^ | Left-to-Right |

&& | Left-to-Right |

|| | Left-to-Right |

.. | Left-to-Right |

? and : | Right-to-Left |

=, +=, -=, *= | Right-to-Left |

, | Left-to-Right |

not | Left-to-Right |

and | Left-to-Right |

or, xor | Left-to-Right |

The arity of an operator can be defined as the number of operands on which it operates.

A **nullary** operator operates on zero operand, a **unary** operator operates on one operand, a **binary** operator operates on two operands and a **listary** operator operates on list of operands.

For example,

3 + 3 ? 2

Arithmetic operators are usually left associative. Here, (3 + 3) evaluates first and then goes to the second (-) operator.

Example

snippet

use 5.010; use strict; use warnings; my $result = ( 5 - 2 + 10 ) * 2; say $result;

Output

26

Operator fixity can be defined as its position relative to its operands.

For example,

- Infix operator appears between its operands..
3 + 2

Here, + operator appears in between the operands 3 and 2

- Prefix operator appears before its operands.
! $a, - 3x

Here, ! and - operator appears before the operands $a and 3.

- Postfix operator appears after its operands,.
$x ++

Here, ++ operator appears after the operands $x.

- Circumfix operators surround its operands. Such as hash constructor and quoting operators..
(qq[...])

- Postcircumfix operators follow certain operands and surround some operands.
$hash{$a}

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