Hi Deepak,
With Information Steward You are able to identify data quality issues. For that you create data quality rules and apply them to your data. When you want to parse, standardize, correct, enrich, format or cleanse your data, then Data Services is the tool to chose.
In other words: The if clause of your description above is the part you would define in IS as a validation rule expression to apply that to your data and see how many records are violating this rule (= how many bad records you have ). The second part, the then case ( = cleanse these bad records ) is not an action taken by Information Steward.
You might use the Cleansing Package Builder component in IS to set up cleansing rules to be used by Data Services, but that is different topic than Validation Rules.
There are lots of great product tutorials here on the SCN, that describe scope, features and functionalities of Information Steward, so you got a understanding of what you can do with IS.
NIels