Perl if-else

Perl if-else statements are used to control the flow of the program. The if statement checks a condition and executes a block of code only if the condition is true, and the else statement executes a block of code if the condition is false.

Syntax

Here is the basic syntax for an if-else statement in Perl:

if (condition) {
    # code to execute if condition is true
} else {
    # code to execute if condition is false
}

The condition can be an expression that evaluates to a Boolean value (true or false). The code block is enclosed in curly braces {}.

Example

Here is an example of an if-else statement in Perl:

my $x = 10;

if ($x > 5) {
    print "x is greater than 5\n";
} else {
    print "x is less than or equal to 5\n";
}

Output:

x is greater than 5

In this example, the condition $x > 5 is true, so the code block inside the if statement is executed.

Nested if-else statements

You can also use nested if-else statements to test multiple conditions. Here is an example:

my $x = 10;
my $y = 5;

if ($x > 5) {
    if ($y > 5) {
        print "x and y are both greater than 5\n";
    } else {
        print "x is greater than 5 but y is less than or equal to 5\n";
    }
} else {
    print "x is less than or equal to 5\n";
}

Output:

x is greater than 5 but y is less than or equal to 5

In this example, the outer if statement checks if $x is greater than 5. If it is, the inner if statement checks if $y is also greater than 5. If it is, the code block inside the inner if statement is executed. If it isn't, the code block inside the inner else statement is executed.

ternary operator

Perl also provides a ternary operator ? : that can be used as a shorthand for an if-else statement. Here is an example:

my $x = 10;
my $result = ($x > 5) ? "x is greater than 5" : "x is less than or equal to 5";
print "$result\n";

Output:

x is greater than 5

In this example, the ternary operator ? : checks if $x is greater than 5. If it is, the first expression before the : is evaluated and assigned to $result. If it isn't, the second expression after the : is evaluated and assigned to $result.

Conclusion

Perl if-else statements can be useful for controlling the flow of your program based on certain conditions. You can use nested if-else statements for more complex conditions, and the ternary operator as a shorthand for if-else statements.