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[英]How to remove both positive and negative numbers from a list in dataframe?
[英]In a dataframe with both positive & negative numbers, how to round positive numbers up and round negative numbers down (both to multiples of 5)?
对于 dataframe 这样的:
data={'A1':[-7.22,-9.432,-0.00111,0.233,17,23,34],
'A2':[-23,-7.2455,-0.00222,0.54,1.345,19,21]}
kk=pd.DataFrame(data)
A1 A2
0 -7.22000 -23.00000
1 -9.43200 -7.24550
2 -0.00111 -0.00222
3 0.23300 0.54000
4 17.00000 1.34500
5 23.00000 19.00000
6 34.00000 21.00000
我想向上舍入正数但向下舍入负数(5 的倍数),例如:
尝试使用此方法仅收到错误
def roundupdown5(x):
if x>=0:
return np.ceil(x/5)*5
else:
return np.floor(x/5)*5
kk[['A1','A2']].apply(lambda x: roundupdown5(x))
谢谢:)
您可以使用applymap()
而不是apply()
kk.applymap(roundupdown5)
结果是
A1 A2
0 -10.0 -25.0
1 -10.0 -10.0
2 -5.0 -5.0
3 5.0 5.0
4 20.0 5.0
5 25.0 20.0
6 35.0 25.0
在构建DataFrame
之前,您可以使用字典和列表理解将roundupdown5()
function 应用于data
的所有值:
import pandas as pd
import numpy as np
data={'A1':[-7.22,-9.432,-0.00111,0.233,17,23,34],'A2':[-23,-7.2455,-0.00222,0.54,1.345,19,21]}
kk=pd.DataFrame(data)
def roundupdown5(x):
if x>=0:
return np.ceil(x/5)*5
else:
return np.floor(x/5)*5
data = {k:[roundupdown5(i) for i in v] for k, v in data.items()}
kk=pd.DataFrame(data)
print(data, kk)
Output:
{'A1': [-10.0, -10.0, -5.0, 5.0, 20.0, 25.0, 35.0], 'A2': [-25.0, -10.0, -5.0, 5.0, 5.0, 20.0, 25.0]} A1 A2
0 -10.0 -25.0
1 -10.0 -10.0
2 -5.0 -5.0
3 5.0 5.0
4 20.0 5.0
5 25.0 20.0
6 35.0 25.0
您可以在绝对值上使用numpy.ceil
并使用numpy.sign
带回符号,然后您将受益于矢量速度:
np.ceil(abs(kk)/5)*5*np.sign(kk)
output:
A1 A2
0 -10.0 -25.0
1 -10.0 -10.0
2 -5.0 -5.0
3 5.0 5.0
4 20.0 5.0
5 25.0 20.0
6 35.0 25.0
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