[英]keyError when trying to drop a column in pandas.
我想從數據中刪除一些行。 我正在使用以下代碼-
import pandas as pd
import numpy as np
vle = pd.read_csv('/home/user/Documents/MOOC dataset original/vle.csv')
df = pd.DataFrame(vle)
df.dropna(subset = ['week_from'],axis=1,inplace = True)
df.dropna(subset = ['week_to'],axis=1,inplace = True)
df.to_csv('/home/user/Documents/MOOC dataset cleaned/studentRegistration.csv')
但它引發以下錯誤-
raise KeyError(list(np.compress(check,subset)))
KeyError: [' week_from ']
怎么了?
我認為需要省略axis=1
,因為默認值是axis=0
用於通過dropna
按檢查NaN
的dropna
集刪除具有NaNs(缺失值)的行,所以解決方案也應簡化為一行:
df.dropna(subset = ['week_from', 'week_to'], inplace = True)
樣品 :
df = pd.DataFrame({'A':list('abcdef'),
'week_from':[np.nan,5,4,5,5,4],
'week_to':[1,3,np.nan,7,1,0],
'E':[5,3,6,9,2,np.nan],
'F':list('aaabbb')})
print (df)
A week_from week_to E F
0 a NaN 1.0 5.0 a
1 b 5.0 3.0 3.0 a
2 c 4.0 NaN 6.0 a
3 d 5.0 7.0 9.0 b
4 e 5.0 1.0 2.0 b
5 f 4.0 0.0 NaN b
df.dropna(subset = ['week_from', 'week_to'], inplace = True)
print (df)
A week_from week_to E F
1 b 5.0 3.0 3.0 a
3 d 5.0 7.0 9.0 b
4 e 5.0 1.0 2.0 b
5 f 4.0 0.0 NaN b
如果要通過為check NaN
指定行來刪除列:
df.dropna(subset = [2, 5], axis=1, inplace = True)
print (df)
A week_from F
0 a NaN a
1 b 5.0 a
2 c 4.0 a
3 d 5.0 b
4 e 5.0 b
5 f 4.0 b
但是如果需要按名稱刪除列的解決方案不同,則需要drop
:
df.drop(['A','week_from'],axis=1, inplace = True)
print (df)
week_to E F
0 1.0 5.0 a
1 3.0 3.0 a
2 NaN 6.0 a
3 7.0 9.0 b
4 1.0 2.0 b
5 0.0 NaN b
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