# ['A', 36], # ['B', 85], # ['C', 15], # ['B', 65], # ['B', 52], # ['A', 89] dataFile = open("data.txt") l = [] for line in dataFile: if line.strip(): l.append(line.strip().split(',')) dataFile.close() res = {} for item in l: k = item[0] if not res.has_key(k): res[item[0]] = [] res[item[0]].append(item[1]) print res