What is String in PHP?

A string in PHP is a sequence of letters, characters, numbers, special characters and arithmetic values or it can be a combination of all. To create a string simply enclose the string in single quotation marks (‘)
Example

$my_string = 'Hello World';

1	$my_string = 'Hello World';

You can also use double quotation marks (“). However, there is s difference between how it works as explained earlier here.

Some String Function examples

1) Calculate Length of a String

The strlen() function is used to find the number of characters inside a string. along with blank spaces inside the string.

Example:

<?php
echo strlen("Hello World"); // Output 11
?>

<?php

echo strlen("Hello World"); // Output 11

2) Count Number of Words in a String

The function str_word_count() counts the number of words in a string.

Example

<?php
echo str_word_count("Welcome to codedecode!"); // outputs 3
?>

<?php

echo str_word_count("Welcome to codedecode!"); // outputs 3

3) Replace Text within Strings

The str_replace() replaces all occurrences of the search text within the target string.

Example:

echo str_replace("world", "Kritika", "Hello world!"); // outputs Hello Kritika!

1	echo str_replace("world", "Kritika", "Hello world!"); // outputs Hello Kritika!

You can always check the official website for all the string functions:

List of all string functions

Using heredoc syntax

Why use heredoc: Before learning what is heredoc I would like you to understand the need for heredoc.
Let’s understand it by taking an example of a string that contains a lot of quotation mark

<?php
$title = "Learning PHP is fun";
$author = "Kritika Shrivastava";
$statement = "In \"$title\" by $author the \"Power of mind is explained\"";
echo $statement;
?>

<?php

$title = "Learning PHP is fun";

$author = "Kritika Shrivastava";

$statement = "In \"$title\" by $author the \"Power of mind is explained\"";

echo $statement;

Here we need to escape double quotes everytime we want to use it. It looks ugly and messy and difficult to manage also. To avoid this you can build a string using heredoc syntax. Inside heredoc, all double quotes and single quotes are interpreted correctly.

Note: there has to be nothing after EOT, not even space.

$title = "Learning PHP is fun";
$author = "Kritika Shrivastava";
$heredoc = <<<EOT
In "$title" by $author the "Power of mind is explained";
EOT;
echo $heredoc;

$title = "Learning PHP is fun";

$author = "Kritika Shrivastava";

$heredoc = <<<EOT

In "$title" by $author the "Power of mind is explained";

EOT;

echo $heredoc;