Perl Cheat Sheet

Hello World:

        
print "Hello, World!\n";
        
    

Variables:

        
# Declaring variables
my $name;
my $age;

# Assigning values
$name = "John Smith";
$age = 25;

# Initializing variables
my $count = 0;
my $isTrue = 1;
        
    

Data Types:

        
# Scalar data types
my $number = 10;
my $floatingPoint = 3.14159;
my $string = "Hello";
my $boolean = 1;

# Array data type
my @array = (1, 2, 3, 4, 5);

# Hash data type
my %hash = (
    key1 => "value1",
    key2 => "value2"
);
        
    

Operators:

        
# Arithmetic operators
my $sum = 5 + 3;
my $difference = 10 - 4;
my $division = 15 / 2;
my $remainder = 15 % 2;
my $product = 4 * 6;

# Comparison operators
my $isEqual = (5 == 5);
my $isGreater = (10 > 5);
my $isLessThanOrEqual = (15 <= 20);

# Logical operators
my $logicalAnd = 1 && 0;
my $logicalOr = 1 || 0;
my $logicalNot = !1;
        
    

Conditional Statements:

        
# If statement
if (condition) {
    # Code to execute if the condition is true
} else {
    # Code to execute if the condition is false
}

# Unless statement
unless (condition) {
    # Code to execute if the condition is false
}

# Switch statement
my $day = 3;
given ($day) {
    when (1) {
        print "Monday\n";
    }
    when (2) {
        print "Tuesday\n";
    }
    when (3) {
        print "Wednesday\n";
    }
    default {
        print "Invalid day\n";
    }
}
        
    

Loops:

        
# While loop
while (condition) {
    # Code to execute while the condition is true
}

# Do-while loop
do {
    # Code to execute
} while (condition);

# For loop
for (my $i = 0; $i < 10; $i++) {
    # Code to execute repeatedly until the condition becomes false
}

# Foreach loop
foreach my $element (@array) {
    print "$element\n";
}
        
    

Subroutines:

        
# Subroutine declaration
sub functionName {
    # Code to execute
}

# Subroutine with parameters
sub multiply {
    my ($a, $b) = @_;
    my $result = $a * $b;
    return $result;
}

# Subroutine call
my $result = functionName(arguments);
        
    

Regular Expressions:

        
# Matching
if ($string =~ /pattern/) {
    # Code to execute if the pattern matches
}

# Substitution
$string =~ s/pattern/replacement/;

# Splitting
my @parts = split /delimiter/, $string;

# Joining
my $newString = join "delimiter", @array;