2

我有一个 csv 文件，其第一列中有重复值，例如：

mg,known,127
mg,unknown,142
pnt,known,37
pnt,unknown,0
lmo,known,75
lmo,unknown,3
sl,known,197
sl,unknown,21
oc,unknown,32
oc,known,163
sv,known,368
sv,unknown,308
az,unknown,6
az,known,241
bug,unknown,1
bug,known,167
li,unknown,15
li,known,174
lg,known,3

我想要做的是构建一个新的 csv 文件，例如：

header1, known, unknown
mg, 127, 142
pnt, 37, 0

我试图弄清楚我如何才能真正构建行：

def read_stats(path):
    has_seen = set()
    with open(writepath, 'wb') as write_csv:
        with open(path, 'r') as csv_file:
            data_reader = csv.reader(csv_file, delimiter=',')
            for line in data_reader:
                if line[0] in has_seen:

这是我目前感到震惊的地方，我是否必须保留指向下一行的指针？

4

1 回答 1

3

这是在OrderedDict中累积结果的一种方法：

>>> import csv
>>> import collections

>>> d = collections.OrderedDict()
>>> for header1, category, value in csv.reader(datafile):
        d.setdefault(header1, {})[category] = value

>>> for header1, m in d.items():
        print ', '.join([header1, m['known'], m['unknown']])

mg, 127, 142
pnt, 37, 0
lmo, 75, 3
sl, 197, 21
oc, 163, 32
sv, 368, 308
az, 241, 6
bug, 167, 1
li, 174, 15

如果您可以假设这些行总是首先与已知组连续成对出现，您可以为 knowns 创建一个中间结果并为 unkwowns 发出一个完整的行：

>>> for header1, category, value in csv.reader(data):
        if category == 'known':
            result = [header1, value]
        else:
            result += [value]
            print ', '.join(result)

mg, 127, 142
pnt, 37, 0
lmo, 75, 3
sl, 197, 21
oc, 163, 32
sv, 368, 308
az, 241, 6
bug, 167, 1
li, 174, 15
于 2013-04-17T03:21:25.103 回答