In this lesson, you will learn how to create, store or manipulate strings in PHP. A string is a type that contains letters, numbers, and symbols or a combination of these.
How to create a string in PHP
The simplest way to create a string in PHP is to enclose the string literal in single or double quotes.
Example of creating a string in PHP
<?php $str1 = "Web design"; $str2 = 'Web development'; echo $str1; echo "<br/>"; echo $str2; ?>
A string can be enclosed with single or double quotes. using a single-quotes make the string to be treated almost literally, whereas using the double-quotes replace variables with their values as well as especially interpreting specific escape sequences.
The escape-sequence replacements are:
\r is replaced by the carriage-return character
\t is replaced by the tab character
\$ is replaced by the dollar sign
\” is replaced by a double-quote
\\ is replaced by a single backslash
Example of creating a string II
<?php $str = 'John'; echo "Hello, $str!<br>"; // Displays: Hello John! echo 'Hello, $str!<br>'; // Displays: Hello, $str! echo '<pre>Hello\tJohn!</pre>'; // Displays: Hello\tJohn! echo "<pre>Hello\tJohn!</pre>"; // Displays: Hello Joh! echo 'o\'reilly'; // Displays: I'll O'reilly ?>
As you can see, in case of single quotes the string was displayed as it is but, in case of double quotes, the value of variable replaced the variable in the string.
Example of creating a string III
<?php $str = 'John'; var_dump($str); ?>
Heredoc in PHP
Heredoc is used to produce a relatively complex and long string as compared to double quotes. If you have to display a paragraph of text longer than one line, you can use echo statements for each line or heredoc for the whole paragraph at once.
The heredoc is created with <<< followed by a delimiting identifier, followed by text starting on the next line, and then closed by the same identifier on its line. The closing identifier must not be indented.
Example of Heredoc
echo <<<TEXT Your text with multiple line can go here. This is a test of how to output the text inside a string longer than one line of code. TEXT;
Your text with multiple line can go here. This is a test of how to output the text inside a string longer than one line of code.
Nowdoc in PHP
The Nowdoc string is similar to the heredoc, but it works like the way string enclosed within single quotes work. No parsing of variables takes place inside the Nowdoc. It is ideal in the situation when you have to use the raw data that do not need to be parsed.
Example of Nowdoc in PHP
echo <<<'TEXT' Your text with multiple line can go here. This is a test of how to output the text inside a string longer than one line of code. TEXT;
Joining Strings in PHP
To concatenate two strings together, use the dot operator. These strings could be stored in variables as well.
Example of joining strings in PHP
$user_name = "John"; echo "Hello ". $user_name;
PHP Strings Functions
Finding the length of a string
The strlen() function is used to find the total number of characters in a string. The function takes a string as a parameter and returns the length of the given string. It will return zero if the string is empty.
Example of stnlen() function
<?php $user_name = "John"; echo "Length of the string is ". strlen($user_name); ?>
It will produce the following output
Length of the string is 4
How to count the number of words in a string
Str_word_count() function counts the number of words insides string.
The syntax is
Str_word_count(string $str [, int $format =0 [, string $charlist ]]):mixed
Example of counting number of word in a string
<?php $my_str = "Good moring everyone!"; echo "Number of words: ". str_word_count($my_str); ?>
This code will output
Number of words: 3
Stripg_tags() function will remove all HTML and PHP tags from a string.
Strip_tags(string $str [,string $allowable_tags]) : string
<?php strip_tags($input, '<br>'); ?>
Changing case of string
Ucfirst() method make a string’s first character uppercase.
ucfirst( string $str) : string
Example of changing case of string
<?php $foo = 'hello world!'; $foo = ucfirst($foo); // Hello world! ?>
strtolower() function will convert a string into lowercase and strtoupper() function will change a string into upper case
Example of strtolower() function
<?php $str = "When you cannot find sunshine, Be sunshine yourself."; echo strtolower($str); echo “<br/>”; echo strtoupper($str); ?>
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