PHP is_numeric() Function
A Program To Find The Length Of A String in PHP And MYSQL With Database | T4Tutorials.com
php - Value in array is a string not an integer - Stack Overflow
PHP Tutorial - Check if a variable is a number or a numeric string in PHP
PHP number_format() function - w3resource
PHP - Check if string starts with a number
PHPyths Buster: A great string performance test! (updated) - Krzych Jończyk
count_chars - Count Number of character of string with PHP | Web Technology Experts Notes
PHP 5 Strings - MEGATEK ICT ACADEMY
Number Functions in PHP - afgprogrammer
PHP - How to convert integer to string? - TutorialKart
Convert an Integer Into a String in PHP | Delft Stack
Array to string conversion in C://... in PHP - Stack Overflow
How to Remove Numbers from String in PHP - Laravel Plug
PHP Program to count the vowels, digits, and spaces in a string | T4Tutorials.com
php - Value in array is a string not an integer - Stack Overflow
PHP - Concatenate string and number
Sum of digits of a input number using string and loop
PHP Implode – Convert Array to String with Join
How to use implode() in PHP (with examples) - Tinkerwell
The Top 9 Most Popular PHP String Functions – vegibit
