Question

这是我想用python更新的csv文件。它有3列：

col1 = [1,2,3,4,5,6,7,8,9,10] 
col2 = [A, A, A, B, C, C, C, C, A, A] 
col3 = []

对于col3中的每个单元格，我想填写一个只有当col2的内容发生变化时才会改变的id号。

在我的例子中，我会得到col3 = [1,1,1,2,3,3,3,3,4,4]

有人给我指路吗？

Answer 1

在Python 3中：

from itertools import groupby
from operator import itemgetter
import csv

with open('f1.csv', newline='') as f_in, open('f2.csv', 'w', newline='') as f_out:
    reader = csv.reader(f_in)
    writer = csv.writer(f_out)
    for i, (key, group) in enumerate(groupby(reader, key=itemgetter(1)), start=1):
        for row in group:
            writer.writerow(row + [i])

如果使用Python 2.7，请将with语句更改为

with open('f1.csv', 'rb') as f_in, open('f2.csv', 'wb') as f_out:

根据csv文件填充行

1 个答案: