Question

作为输入，我有一个.csv文件，如：

user, withdraw, date
50D8BF0DA22D6C914777D8F59DAAB4D8, -125, 01-02-2015
674BCF0CD236621E5680073334A73C32, -5, 01-02-2015
E17E1691D35FB2FB675E3B787B8BEDF1, -845, 01-02-2015
50D8BF0DA22D6C914777D8F59DAAB4D8, -250, 01-02-2015
674BCF0CD236621E5680073334A73C32, -98, 01-02-2015
50D8BF0DA22D6C914777D8F59DAAB4D8, -17, 01-02-2015

我想识别所有类似的哈希＆＃39;代码并更改标签，例如＆＃39; user1＆＃39;，＆＃39; user2＆＃39;，＆＃39; user3＆＃39; ...等等。

我一直试图用 pandas 取得成功。知道我能做什么吗？

Answer 1

首先将CSV读入Pandas DF：

df = pd.read_csv('/path/to/file.csv', skipinitialspace=True)

的产率：

In [84]: df
Out[84]:
                               user  withdraw        date
0  50D8BF0DA22D6C914777D8F59DAAB4D8      -125  01-02-2015
1  674BCF0CD236621E5680073334A73C32        -5  01-02-2015
2  E17E1691D35FB2FB675E3B787B8BEDF1      -845  01-02-2015
3  50D8BF0DA22D6C914777D8F59DAAB4D8      -250  01-02-2015
4  674BCF0CD236621E5680073334A73C32       -98  01-02-2015
5  50D8BF0DA22D6C914777D8F59DAAB4D8       -17  01-02-2015

现在我们可以分解user列：

In [85]: df['user'] = 'user' + pd.Series((pd.factorize(df.user)[0]+1).astype(str))

In [86]: df
Out[86]:
    user  withdraw        date
0  user1      -125  01-02-2015
1  user2        -5  01-02-2015
2  user3      -845  01-02-2015
3  user1      -250  01-02-2015
4  user2       -98  01-02-2015
5  user1       -17  01-02-2015

并将DF写回csv：

df.to_csv('/path/to/file_new.csv', index=False)

Answer 2

您需要首先构建用户词典，如下所示：

import csv

hashes = {}
user_number = 1
entries = []

with open('input.csv', 'rb') as f_input:
    csv_input = csv.reader(f_input, skipinitialspace=True)
    header = next(csv_input)

    for row in csv_input:
        user = row[0]

        if user not in hashes:
            hashes[user] = "user{}".format(user_number)
            user_number += 1

        row[0] = hashes[user]
        entries.append(row)

with open('output.csv', 'wb') as f_output:
    csv_output = csv.writer(f_output)
    csv_output.writerow(header)
    csv_output.writerows(entries)

给你一个output.csv包含：

user,withdraw,date
user1,-125,01-02-2015
user2,-5,01-02-2015
user3,-845,01-02-2015
user1,-250,01-02-2015
user2,-98,01-02-2015
user1,-17,01-02-2015

如何更改.csv文件的所有示例中的特定元素？

2 个答案: