pandas 计数唯一行 [英] Pandas Counting Unique Rows

问题描述

我有一个类似于的熊猫数据框:

I have a pandas data frame similar to:

ColA ColB
1    1
1    1
1    1
1    2
1    2
2    1
3    2

我希望输出的功能与计数器.我需要知道每行显示多少次(所有列都相同.

I want an output that has the same function as Counter. I need to know how many time each row appears (with all of the columns being the same.

在这种情况下，正确的输出将是:

In this case the proper output would be:

ColA ColB Count
1    1    3
1    2    2
2    1    1
3    2    1

我尝试了某种方式:

df.groupby(['ColA','ColB']).ColA.count()

但这给我带来了一些丑陋的输出，我在格式化时遇到了困难

but this gives me some ugly output I am having trouble formatting

推荐答案

您可以使用 reset_index :

You can use size with reset_index:

print df.groupby(['ColA','ColB']).size().reset_index(name='Count')
   ColA  ColB  Count
0     1     1      3
1     1     2      2
2     2     1      1
3     3     2      1

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