Question

对于pandas数据帧的特定列我想使元素全部为大写并替换空格

import pandas as pd

df = pd.DataFrame(data=[['AA 123',00],[99,10],['bb 12',10]],columns=['A','B'],index=[0,1,2])

# find elements 'A' that are string
temp1 = [isinstance(s, str) for s in df['A'].values]

# Make upper case and replace any space
temp2 = df['A'][temp1].str.upper()
temp2 = temp2.str.replace(r'\s', '')

# replace in dataframe
df['A'].loc[temp2.index] = temp2.values

我得到了

C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\indexing.py:194: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame

See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
  self._setitem_with_indexer(indexer, value)

有什么建议可以避免这种警告或更好的方法来做我想做的事情吗？

Answer 1

您可以使用mat选择要修改的行来简化此操作：

numpy.where

Answer 2

使用 str.upper

replace

df['A'] = df.A.str.upper().replace('\s+', '', regex=True).fillna(df['A'])

       A   B
0  AA123   0
1     99  10
2   BB12  10

Answer 3

您可以用

替换最后一行

df.loc[temp2.index, 'A'] = temp2.values

制作大写并替换列数据框中的空格

3 个答案: