PHP String Functions
A string is basically a collection of characters. It is a data type in PHP. A function in PHP is a unit of code that returns a value based on an input or parameter and processing based on the codes.
Functions are basically a set of in a string that is used to manipulate this data type for different uses and requirements. Common PHP String functions include strrev(), strpos(), str_replace() and many more. The basic need of a string function is to help in completing specific tasks relating to a string. It could be reversing, replacing or even searching for text within strings.
PHP String functions are used to manipulate strings in order to perform a specific task/function when the user has given input. This is one of the most commonly used functions in PHP and if you are aspiring for a job as an SDE in PHP, learning string functions is a must.
Below is a list of the most commonly asked interview questions regarding String functions in PHP. Have a look or even download it in PDF format to read it later.
Most Frequently Asked PHP String Functions
trim() removes all blank spaces or whitespace or other (specified) characters from both sides of a string.
$var = “ Best Interview Questions ”
echo $var;
Types:
- ltrim() – It removes whitespace/other specified characters from the left side of a string.
- rtrim() - It removes whitespace/other specified characters from the right side of a string.
$var = “Best Interview Questions”;
ltrim(“Best”, $var);
rtrim(“Questions”, $var);
We can use str_replace() method to replace a text in a string with another string.
str_replace("interview","interviews","Best interview questions!");
strtoupper("Best Interview Questiomns");
// Output: BEST INTERVIEW QUESTIONS
You can use nl2br() to insert line break in the string.
nl2br("Best Interview \n Questions");
To find the position of a character inside a string in PHP, use the strpos() function in the following way:
$pos = strpos($string, $char);
You can use strtolower() to convert any string to lowercase.
strtolower('Best Interview Questions');
// OUTPUT: best interview questions
To limit the characters in a PHP string, use the following code:
if (strlen($str) > 10)
$str = substr($str, 0, 6) . '...';
In the above code, if the str value is greater than 10, the output will display the final result from 0 to the 6th character of the said string.
For this, the str_split() function can be used. It will convert your string into an array of individual characters where you can enter the start and endpoint of the characters you wish to see.
$str = "Hello";
$arr1 = str_split($str);
print_r($arr1);
Output:
Array
(
[0] => H
[1] => e
[2] => l
[3] => l
[4] => o
)
Here’s a code to replace all the text between two specific characters:
function replace_all_text_between($str, $start, $end, $replacement) {
$replacement = $start . $replacement . $end;
$start = preg_quote($start, '/');
$end = preg_quote($end, '/');
$regex = "/({$start})(.*?)({$end})/";
return preg_replace($regex,$replacement,$str);
}