Change Product Category Based on Keywords - CSV File

I need a script developing which will enable me to change product categories in datafeeds based on keywords. The datafeeds are provided in CSV format. In some cases products have been placed in the wrong category. Such as women's clothing in the Men's Clothing category. So you will need to create a number of rules to find products that are currently in the wrong category, and then reassign the products to the correct category. This will need to be done using keywords. For example, if a product in the mens clothing category contains the keyword "womens" in the product title, it will need to be reassigned to women's clothing. Or if a product in mens clothing (top level category) contains the keyword "trousers" or "jeans" it would be reassigned to the Mens Trousers subcategory.