InbuiltStringFunction.php

<?php
//concatenation in php
$str1="Greesma";
$str2="Thapa";
$fullname=$str1." ".$str2;
echo $fullname;
echo "<br>";

//length of a string
echo strlen($str1);
echo "<br>";

//wordcount of a string
$a="the quick brown fox jumps over a lazy dog";
echo str_word_count($a);
echo "<br>";

//replace a word in a string
echo str_replace("fox", "wolf", $a);
echo "<br>";

//reverse function 
echo strrev($a);
echo "<br>";

//uppercase
echo strtoupper($str1);
echo "<br>";

//lowercase
$d="HELLO";
echo strtolower($d);
echo "<br>";

//position of a word
echo strpos($a, "quick");
echo "<br>";

//other functions
echo substr($a, 5);//gives all the word with and after index 5
echo "<br>";

echo substr($a, 4, 9); //find the word between two given indexes i.e. between 4 and 9
echo "<br>";

$g=" baby";
echo trim($g); //removes unwanted spaces
echo "<br>";

echo "$g[4]";//prints the character at the index 1