why should we use ‘filters’ in pig scripts?

Filters are similar to where clause in SQL.filter which contain predicate.If that predicate evaluates to true for a given record, that record will be passed down the pipeline. Otherwise, it will not.predicate contain different operators like ==,>=,<=,!=.so,== and != can be applied to maps and tuples.

A= load ‘inputs’ as(name,address)

B=filter A by symbol matches ‘CM.*’;