How to Concatenate two or more string in PHP

We can concatenate two or more string in PHP by concatenation operator(“.”);
Example 1 :

<?php
$string1="Hello";
$string2="World !!";
$string3=$string1.$string2;
echo $string3;
?>

Output : HelloWorld !!
Example 2:  if you want to add space between two strings

<?php
$string1="Hello";
$string2="World !!";
$string3=$string1." ".$string2;
echo $string3;
?>

Output : Hello World !!
Example 3:  Concatenate more than two strings

<?php
$string1="Welcome to";
$string2="PHPGurukul";
$string3="Programming Blog";
$string4=$string1.$string2.$string3;
echo $string4;
?>

Output : Welcome to PHPGurukul Programming Blog