String concatenation operator .

Perl
Operators
here

You can concatenate strings using the string concatenation operator ".".

my $str3 = $str1 . $str2;

This is an example to concatenate strings.

my $str1 = 'ABC';
my $str2 = 'DEF';
my $str3 = $str1 . $str2;

The string "$str3" becomes "ABCDEF".

Note that Perl does not concatenate strings with the addition operator "+". "+" Is used to add numbers.

How to use with variable expansion

If the string consists only of variable, it is easy to write using variable expansion.

my $str1 = 'ABC';
my $str2 = 'DEF';
my $str3 = "$str1 $str2";

The string concatenation operator is useful when used in combination with functions.

my @nums = (1, 2, 3);
my $title = 'Number:';
my $output = $title . join(',', @nums) . "\n";

Reference: join function

Special assignment operator

You can use the special assignment operator ".=" to concatenate to its own string.

my $str1 = 'ABC';
$str1 .= 'DEF';

The string "$str1" becomes "ABCDEF".

Repeat operator

You can use the repeat operator "x" to concatenate the same string multiple times.

my $str = 'ABC' x 3;

The string "$str" becomes "ABCABCABC".

Example program

This is an example to concatenate strings.

use strict;
use warnings;

# 1: String concatenation
my $str1 = "1";
my $str2 = "2";
print "\$str1 = $str1\n";
print "\$str2 = $str2\n\n";

my $cat_str = $str1 . $str2;

print "1: String concatenation\n";
print "\$cat_str = $cat_str\n\n";

print "If you connect with +, it will be calculated\n";
my $sum_str = $str1 + $str2;
print "\$sum_str = $sum_str\n\n";

# 2: Repeat and concatenate the same string.
my $multi_cat_str = $str1 x 5;
print "2: Repeated concatenation\n";
print "\$multi_cat_str = $multi_cat_str\n";

Output:

$str1 = 1
$str2 = 2

1: String concatenation
$cat_str = 12

If you connect with +, it will be calculated
$sum_str = 3

2: Repeated concatenation
$multi_cat_str = 11111

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