使用python，我需要根据CSV文件中两列中的两个键取平均值

Question

我有3列的csv文件

TMC, EPOCH, Time
11C12, 1, 24
11C12, 1, 34
11C12, 2, 56
11C12, 2, 78
11C13, 1, 56
11C13, 2, 45
11C13, 2, 64
11C13, 3, 32
11C13, 3, 28

现在，我想拥有一个average.py文件，该文件可以计算TMC，EPOCH每种组合的平均时间，并将其写入txt或csv文件

所需的输出是：

TMC, EPOCH, Average Time
11C12, 1, average value 
11C12, 2, average value
11C13, 1, average value
11C13, 2, average value
11C13, 3, average value

Answer 1

使用defaultdict使用前两列作为关键字对元素进行分组，然后附加时间，然后取平均值并写入新的csv：

import csv
from collections import defaultdict

with open("in.csv") as f, open("average.csv", "w") as out:
    wr = csv.writer(out)
    d = defaultdict(list)
    head = next(f)
    out.write(head)
    for row in csv.reader(f):
        d[tuple(row[:2])].append(int(row[-1]))

    for k, v in d.items():
        out.write("{},{},{}\n".format(k[0], k[1], sum(v, 0.0) / len(v)))

输出：

TMC,EPOCH,Time
11C12,1,29.0
11C12,2,67.0
11C13,1,56.0
11C13,2,54.5
11C13,3,30.0

如果要保持顺序，首先可以看到元素，则可以使用OrderedDict ：

import csv
from collections import OrderedDict

with open("in.csv") as f, open("average.csv", "w") as out:
    wr = csv.writer(out)
    d = OrderedDict()
    head = next(f)
    out.write(head)
    for row in csv.reader(f):
        d.setdefault(tuple(row[:2]), []).append(int(row[-1]))

    for k, v in d.items():
        out.write("{},{},{}\n".format(k[0], k[1], sum(v, 0.0) / len(v)))