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[英]For each value in a column, how to count the number of unique values in its row?
[英]How to count the unique values of each row in one column with python?
我有這樣一個數據框:
id countries
01 [UK,UK,UK,US]
02 [US,US,US,US]
03 [FR,UK,CN,US]
我想計算每個ID有多少個國家。 像結果應該像:
id countries counts
01 [UK,UK,UK,US] 2
02 [US,US,US,US] 1
03 [FR,UK,CN,US] 4
如果值是list
請將其轉換為set
並獲取length
:
print (type(df.loc[0, 'countries']))
<class 'list'>
df['counts'] = df['countries'].apply(lambda x: len(set(x)))
print (df)
id countries counts
0 1 [UK, UK, UK, US] 2
1 2 [US, US, US, US] 1
2 3 [FR, UK, CN, US] 4
或者,如果值是strings
請先刪除[]
並拆分:
print (type(df.loc[0, 'countries']))
<class 'str'>
df['counts'] = df['countries'].str.strip('[]').str.split(',').apply(lambda x: len(set(x)))
print (df)
id countries counts
0 1 [UK,UK,UK,US] 2
1 2 [US,US,US,US] 1
2 3 [FR,UK,CN,US] 4
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