Finding a small list of strings in a large list of strings (Python)

import csv

def read_input(filename):
    f = open(filename)
    return csv.DictReader(f, delimiter = ',')

def search_filter(src, term):
    term = term.lower()
    for s in src:
        if term in map(str.lower, s.values()):
            yield s

def query(src, terms):
    terms = terms.split()
    for t in terms:
        src = search_filter(src, t)
    return src

def print_query(q):    
    for row in q:
        print row

I tried to split the logic into small, re-usable functions.

First, we have read_input which takes a filename and returns the lines of a CSV file as an iterable of dicts.

The search_filter filters a stream of results with the given term. Both the search term and the row values are changed to lowercase for the comparison to achieve case-independent matching.

The query function takes a query string, splits it into search terms and then makes a chain of filters based on the terms and returns the final, filtered iterable.

>>> src = read_input("input.csv")
>>> q = query(src, "Romance 2003")
>>> print_query(q)
{'genre': 'Romance', 'year': '2003', 'name': 'Private Series', 'author': 'Kate Brian'}
{'genre': 'Romance', 'year': '2003', 'name': 'Geisha', 'author': 'Mary Door'}

Note that the above solution only returns full matches. If you want to e.g. return the above matcher with the search query "Roman 2003", then you can use this alternative version of search_filter:

def search_filter(src, term):
    term = term.lower()
    for s in src:
        if any(term in v.lower() for v in s.values()):
            yield s