Built-in PHP functions e.g., strlen(), array_push()
PHP programming language provides programmers with a rich set of ready-made built-in functions that help them perform various functional tasks in PHP function programs, such as string manipulation, array handling, and mathematical operations.
So, let’s explore the built-in multiply function method in PHP function programs.
String Functions in PHP.
strlen() function.
The strlen() function is used to find the length of a text string in PHP function programs. Here, strlen() returns the number of characters in the current string.
<?php
$message = “welcome to, vcanhelpsu”;
echo strlen($message); // Result – 22
?>
str_replace() in PHP.
This function replaces all strings of text in a text search string with another string of text in a PHP function program.
<?php
$message = “learn php programming”;
$repmesage = str_replace(“php”, “java”, $message);
echo $repmesage; // Result – learn java programming
?>
substr() in php.
The PHP function extracts a particular text or information from a text search string in a program and displays it on the console screen.
<?php
$language = “php programming, javascript programming”;
echo substr($language, 16, 11); // Result – javascript
?>
strpos() in php.
The PHP function finds and displays the first occurrence of a substring in a text search string in a program.
<?php
$language = “python java matlab programming.”;
echo strpos($language, “matlab”); // Result – 12 display the position of “matlab”
?>
Array function in PHP.
array_push() in PHP.
This PHP function adds one or more array elements to the end of an array declared in the program.
<?php
$array_data = [7, 8, 9, 10];
array_push($array_data, 11, 12, 13);
print_r($array_data); // Result – Array ( [0] => 7 [1] => 8 [2] => 9 [3] => 10 [4] => 11 [5] => 12 [6] => 13)
?>
array_pop() in PHP.
This PHP function removes the displayed array element stored at the end of an array declared in the program.
<?php
$array_data = [7, 8, 9, 10];
array_pop($array_data);
print_r($array_data); // Result – Array ( [0] => 7 [1] => 8 [2] => 9 )
?>
array_merge() in PHP.
The PHP function declared in the program merges one or more array element data types.
<?php
$first_array = [22, 44, 55];
$second_array = [77, 88, 99];
$merge_array = array_merge($first_array, $second_array);
print_r($merge_array); // Result – Array ( [0] => 22 [1] => 44 [2] => 55 [3] => 77 [4] => 88 [5] => 99 )
?>
in_array() in PHP.
A PHP function declares an array to check if a value exists in the array.
<?php
$laptop = [“hp laptop”, “macbook”, “lenovo laptop”];
echo in_array(“macbook”, $laptop) ? “Yes” : “No”; // Result – Yes
?>
Mathematical functions in PHP.
abs() in PHP.
A PHP function declares and to return the absolute value of a numeric value.
<?php
echo abs(-18.78); // Result – 18.78
?>
round() in PHP.
A PHP function declares an array to return a floating-point numeric value as a rounded floating-point or nearest integer value.
<?php
echo round(7.789000, 2); // Result – 7.79
?>
rand() in PHP.
This PHP function generates a random value between two numeric values given in the program.
<?php
echo rand(10, 20); // Result – display a random number between 10 and 20
?>
max() in PHP.
This PHP function returns the highest or maximum numeric value in an array or value list given a numeric value given in the program.
<?php
echo max(88, 77, 101, 409, 987); // Result – 987
?>
Date and time functions in PHP.
date() in PHP.
The date function here formats and displays the current date and time in a PHP program.
<?php
echo date(“Y-m-d H:i:s”); // Result – It displays the current date and time as, 2025-10-02 06:48:14
?>
strtotime() in PHP.
Here the strtotime() function in PHP program displays a string in Unix timestamp format on the console screen.
<?php
$timestamp = strtotime(“2025-10-02”);
echo $timestamp; // Result – A Unix timestamp representing October 02, 2025
?>
time() in PHP.
Here the time function in PHP program returns the current Unix timestamp on the console screen.
<?php
echo time(); // Result – It used to display the current Unix timestamp e.g., 1759388184
?>
File function in PHP.
fopen() in PHP.
Opens a file or URL for read or write operations in a PHP file handling program.
<?php
$file = fopen(“sample.txt”, “r”);
if ($file) {
echo “File open process success”;
fclose($file);
}
?>
file_get_contents() in PHP.
Reads file contents in a string format in a PHP file handling program.
<?php
$file_content = file_get_contents(“sample.txt”);
echo $file_content;
?>
fwrite() in PHP.
Creates data and information in an existing file in a PHP file handling program.
<?php
$write_file = fopen(“testfile.txt”, “w”);
fwrite($write_file, “welcome to, vcanhelpsu”);
fclose($write_file);
?>
Type Checking Functions in PHP
is_array() in PHP.
This PHP function checks whether a variable is an array or not.
<?php
$is_array = [0, 9, 8, 4];
echo is_array($is_array) ? “Yes” : “No”; // Result – Yes
?>
is_int() in PHP.
This PHP function checks whether a variable is an integer or not.
<?php
$storage = 98;
echo is_int($storage) ? “Yes” : “No”; // Result – Yes
?>
is_string() in PHP.
This PHP function checks whether a user-declared variable is a string or not.
<?php
$variable = “java, php”;
echo is_string($variable) ? “Yes” : “No”; // Result – Yes
?>
Other useful functions in PHP.
isset() in PHP.
This PHP function checks whether a variable is set or not and is not null.
<?php
$variable = “vcanhelpsu”;
echo isset($variable) ? “Set” : “Not set”; // Result – Set
?>
empty() in PHP.
This PHP function checks whether a variable is empty or not, e.g., “”, 0, or null.
<?php
$variable = “”;
echo empty($variable) ? “Empty” : “Not empty”; // Result – Empty
?>
print_r() in PHP.
This PHP function checks the value of a variable in a program and prints human-readable information about it. It is most commonly used for arrays.
<?php
$array = [98, 44, 22, 11];
print_r($array); // Result – Array ( [0] => 98 [1] => 44 [2] => 22 [3] => 11 )
?>
A summary of built-in functions in PHP programming.
- String functions – These string functions are used to apply various string function operations like strlen(), str_replace(), substr().
- Array functions – These array functions are used to apply array operations like array_push(), array_pop(), array_merge(), and in_array().
- Mathematical functions – These mathematical functions abs(), round(), rand(), max() are used to solve mathematical operations.
- Date and time functions – Date and time functions date(), strtotime(), time() are used to display date and time information in the program.
- File functions – These file handling functions fopen(), file_get_contents(), fwrite() are used to control and manage file operations.
- Type checking – Here the type checking functions is_array(), is_int(), is_string() check the value type.
- Miscellaneous – These are other functions, which are used in isset(), empty(), print_r() and other PHP programming operations.
