To find if a number is odd or even you can use one of two operators.

The modulo operator (% in PHP) can be used to calculate the remainder of the value divided by 2. This gives a value of 0 for even numbers and a value of 1 for odd numbers. This can be used in an if statement as 0 will equate to false and 1 will equate to true.

To round a number in PHP you can use one of three functions, these are round(), ceil() and floor(). All of these functions take number as the input and will round the value depending on the function used.

To round to the closest integer use the round() function.

The is_numeric() function in PHP can be used to see if a number contained in a string is numeric. The function returns true is the variable can be parsed into a string, otherwise it returns false. Here are some examples:

Here is a function to generate a select box for a HTML form. The three parameters are:

When debugging PHP code the print_r can be useful if you want to know what an array or object contains. It will take any variable as input and will print off as much information as it can about that variable. So the following code.