String functions in PHP | What is string in PHP | Single Quote, Double Quote string in PHP

Custom Functions in PHP |Call by Reference and Call by Value Functions in PHP

What is a PHP string?

Sequence of characters is known as string. There are different ways to define a string statement in PHP, they are known as PHP strings. There are different ways to specify a string literal in PHP. The string variables can contain alphanumeric characters.

Single quoted

Let’s now look at the four different ways of creating PHP string functions and string manipulation in PHP.

Creating PHP Strings Using Single quotes: The simplest way to create a string is to use single quotes. Let’s look at an example that creates a simple string in PHP.

<?php 
$str='Hello text within single quote'; 
echo $str; 
var_dump('You need to be logged in to view this page');
//If the single quote is part of the string value, it can be escaped using the backslash.
echo 'I \'ll be back after 20 minutes';
?>

Hello text within single quote
string(42) "You need to be logged in to view this page"
I'll be back after 20 minutes

Double quoted

The double quotes are used to create relatively complex strings compared to single quotes. Variable names can be used inside double quotes and their values will be displayed.

Let’s look at an example.

<?php 
$str="Hello text within double quote"; 
echo $str; 
$name='Alicia';
echo "$name is friends with kalinda";
?>

Hello text within double quote
Alicia is friends with kalinda

What are PHP string functions?

PHP string functions helps to manipulate strings in different ways.

We are now going to look at some of the commonly used string functions in PHP

strtolower() function- returns strings in lower case.

<?php 
$str = "My name is KHAN";
$str = strtolower($str);
echo $str; 
?>

Output:

my name is khan

strtoupper() function-returns strings in lower case.

<?php 
$str = "My name is KHAN";
$str = strtoupper($str);
echo $str; 
?>

Output:

MY NAME IS KHAN

ucfirst() function- returns 1st character of a string statement in upper case.

<?php 
$str = "my name is KHAN";
$str = ucfirst($str);
echo $str; 
?>

Output:

My name is KHAN

lcfirst() function- returns 1st character of a string statement in upper case.

<?php 
$str = "MY name IS KHAN";
$str = lcfirst($str);
echo $str; 
?>

Output:

mY name IS KHAN

ucwords() function- returns 1st letter of each word of a string statement in upper case.

<?php 
$str = "my name is Sonoo jaiswal";
$str = ucwords($str);
echo $str; 
?>

Output:

My Name Is Sonoo Jaiswal

strlen() – Return the Length of a String

<?php 
$str = "my name is Sonoo jaiswal";
$str = strlen($str);
echo $str; 
?>

Output:

12

str_word_count() – Count number of Words in a String

<?php echo str_word_count("Hello world!"); // outputs 2 ?>

Output:

2

strrev() – Reverse a String

<?php 
$str = "my name is Sonoo jaiswal";
$str = strrev($str);
echo $str;
?>

Output:

!dlrow olleH

strpos() – Search For a Text Within a String

<?php 
echo strpos("Hello world!", "world"); // outputs 6 
?>

Output:

6

str_replace() – Replace Text Within a String

<?php 
echo str_replace("world", "Dolly", "Hello world!"); // outputs Hello Dolly! 
?>

Output:

Hello Dolly!

https://php.net/manual/en/ref.strings.php