How to Check If a Variable is an Integer, a Float, a Number, NaN, an Infinite or a Numeric in PHP?

PHP provides auto data type conversion so you can assign int value in the beginning and change it to float in the middle and PHP won't make a sound!

An integer data type is a non-decimal number between -2147483648 and 2147483647. So, any number out of that range is considered and stored as a float.

So, we need to be careful while assigning values in a lengthy program or calculation as the data type change can cause some errors. 

Here are the functions we can use to check if the number is integer.

• is_int()
• is_integer() 
• is_long()

To check whether the number is float use these following functions:

• is_float()
• is_double()

Now, the float has it's own limit as well. If the number is greater than the PHP_FLOAT_MAX than it's infinite number. We can check that using following functions.

• is_finite()
• is_infinite()

To check whether the value is not a number, use this

• is_nan()

Lastly, to check whether the variable is numeric or not, use following function

• PHP is_numeric()

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