PHP Filters are extensions use to validate inputs from a user or web services .
We must use filter functions to filter the data
Mainly two types of files are out there (Validating filters and sanitizing filters)
filter_var(variable, filter, options)
Variable : its holds the values to be filtered
filter : Its the id of filter .its an optional and the default filter is FILTER_SANITIZE_STRING
options : can be an array of options/flags