Sumit Bansal

We’re going to use several string functions together. Let’s take the string testing testing Username:Michele Davis and retrieve only the name.

Using several functions together to extract a portion of a string

$test_string="testing testing Username:Michele Davis";
$position=strpos($test_string,"Username:");

echo "$test_string
";
echo "$position
";
echo substr($test_string,$start);
?>

This Code Return

testing testing Username:Michele Davis
16
Michele Davis

Note: The number 16 in our example is the position of our username

Use strpos to search for Username: and return its position in the string with zero being the first position. Use strlen to add on to that position to find where you need to start extracting from the $test_string. To extract the name, use substr, which takes the string as a parameter, returning everything after the $position character in the string.

To detect whether a string is part of another string, use strstr. This function takes two parameters: the string to search through and the string to search for. It is not case sensitive; if you want to use a function that is case sensitive, use stristr. Lastly, there is strops, which finds the position of every first occurrence of the string you specified.

Detecting whether a string is contained in another string

$password="secretpassword1";

if (strstr($password,"password")){
echo('Passwords cannot contain the word "password".');
}
else {
echo ("Password accepted.");
}
?>

This Code Returns: Passwords cannot contain the word “password”.

PHP provides functionality for changing the case of a string to all uppercase, all lowercase, or the first letter of a word to uppercase. The commands are strtoupper, strtolower, and ucwords, respectively.

Using the word case functions

$username="John Doe";
echo("$username in upper case is ".strtoupper($username).".
");
echo("$username in lower case is ".strtolower($username).".
");
echo("$username in first letter upper case is ".ucwords($username).".
");
?>

The above code returns:

John Doe in upper case is JOHN DOE.
John Doe in lower case is john doe.
John Doe in first letter upper case is John Doe.

The substring functions provide a way to extract a portion of a string. All that’s needed is the string to work with, the position to start from, and how many characters to extract. Use the LEFT, RIGHT, and SUBSTRING functions to do the extraction

LEFT:- Takes the string and the number of characters to extract from the start of the string.
For Example: LEFT(’6128238193′,3)

RIGHT:- Takes the string and the number of characters to extract from the end of the string.
For Example: SUBSTR(’6128238193′,4,3)

SUBSTR:- Takes the string and the number of characters to extract beginning with a certain position in the string.
For Example: RIGHT(’6128238193′, 4)

Adding the formatting to a phone number using LEFT, RIGHT,and SUBSTR

For example: if a database has phone numbers stored in a 10-digit string without any formatting, the numbers could be displayed with the formatting by using the code

SELECT CONCAT('(',LEFT('6128238193',3),')',SUBSTR('6128238193',4,3),'-',RIGHT('6128238193', 4));

These Commands Return: (612)823-8193