import pandas as pd
qry = pd.DataFrame.from_dict({'Keyword': ['NewWordsWithFriends',
    'com.fingerarts.sudoku'], 'Game': ['Words With Friends',
    'Sudoku by FingerArts']})
df = pd.DataFrame.from_dict({'user-agent': [
    'NewWordsWithFriendsFree/2.3 CFNetwork/672.1.15 Darwin/14.0.0',
    'iPhone3,1; iPhone OS 7.1.2; com.fingerarts.sudoku2; 143441-1,24']})
keywords = qry.Keyword.tolist()
games = qry.Game.tolist()

def select(x):
    for key, game in zip(keywords, games):
        if key in x:
            return game
df['GameName'] = df['user-agent'].apply(select)
Python Pandas: таблица поиска путем поиска подстроки