pandas - 每列计数不同的值 [英] Pandas - count distinct values per column
本文介绍了 pandas - 每列计数不同的值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个如下所示的数据框:
Id ActivityId ActivityCode
1 2 3
1 2 4
1 3 2
我需要计算在上面的例子中,id 1会返回2,因为这个id有两个不同的活动ID。
p> SQL看起来就是这样:
SELECT COUNT(DISTINCT ActivityId) FROM table GROUP BY Id
我如何在熊猫中做到这一点?
(如果可能的话,我想知道是否有方法在字典中获得结果,而不需要手动迭代)
解决方案
print(df)
Id ActivityId ActivityCode
0 1 2 3
1 1 2 4
2 1 3 2
3 2 8 7
df = df.groupby('Id')['ActivityId']。nunique()
print(df)
Id
1 2
2 1
名称:ActivityId,dtype:int64
dict
add Series.to_dict
:
d = df .groupby('Id')['ActivityId']。nunique()。to_dict()
print(d)
{1:2,2:1}
I have a dataframe that looks like this:
Id ActivityId ActivityCode
1 2 3
1 2 4
1 3 2
I need to get a count of the distinct Activity IDs that the Id is related to.
In the example above, id 1 would return 2 since there're 2 distinct activity ids for that id.
The SQL would look this way:
SELECT COUNT(DISTINCT ActivityId) FROM table GROUP BY Id
How do I do this in pandas?
(And if possible, I'd like to know if there's a way to get the result in a dictionary, without iterating manually)
解决方案
I think you need groupby
with nunique
:
print (df)
Id ActivityId ActivityCode
0 1 2 3
1 1 2 4
2 1 3 2
3 2 8 7
df = df.groupby('Id')['ActivityId'].nunique()
print (df)
Id
1 2
2 1
Name: ActivityId, dtype: int64
And for dict
add Series.to_dict
:
d = df.groupby('Id')['ActivityId'].nunique().to_dict()
print (d)
{1: 2, 2: 1}
这篇关于 pandas - 每列计数不同的值的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文