gist for https://www.v2ex.com/t/463296

parse_log.py

result = dict()
filepath = r"D:\test.log"
with open(filepath, "r") as fin:
    for line in fin:
        parts = line.split(", ")
        tag = parts[0]
        value = float(parts[1])
        result.setdefault(tag, []).append(value)
for k, v in result.iteritems():
    print k, sum(v), sum(v)/len(v)