Python:按对剥离列名

Question

我有一个DataFrame的列，看起来像这样:

df=pd.DataFrame(columns=['(NYSE_close, close)','(NYSE_close, open)','(NYSE_close, volume)', '(NASDAQ_close, close)','(NASDAQ_close, open)','(NASDAQ_close, volume)'])
df:
(NYSE_close, close) (NYSE_close, open) (NYSE_close, volume) (NASDAQ_close, close) (NASDAQ_close, open) (NASDAQ_close, volume)

我想删除下划线之后的所有内容，并在逗号之后添加任何内容，以得到以下内容:

df:
NYSE_close  NYSE_open  NYSE_volume  NASDAQ_close  NASDAQ_open  NASDAQ_volume

我试图去掉列名，但它用nan代替了它。有什么建议吗?

提前谢谢你。

Answer 1

您可以使用re.sub提取列名的适当部分，并将其替换为:

import re
df=pd.DataFrame(columns=['(NYSE_close, close)','(NYSE_close, open)','(NYSE_close, volume)', '(NASDAQ_close, close)','(NASDAQ_close, open)','(NASDAQ_close, volume)'])
df.columns = [re.sub(r'(([^_]+_)w+, (w+))', r'12', c) for c in df.columns]

输出:

Empty DataFrame
Columns: [NYSE_close, NYSE_open, NYSE_volume, NASDAQ_close, NASDAQ_open, NASDAQ_volume]
Index: []

Answer 2

你可以:

import re
def cvt_col(x):
s = re.sub('[()_,]', ' ', x).split()
return s[0] + '_' + s[2] 
df.rename(columns = cvt_col)
Empty DataFrame
Columns: [NYSE_close, NYSE_open, NYSE_volume, NASDAQ_close, NASDAQ_open, NASDAQ_volume]
Index: []

Answer 3

使用列表推导式，两次:

step1 = [ent.strip('()').split(',') for ent  in df]
df.columns = ["_".join([left.split('_')[0], right.strip()]) 
for left, right  in step1]
df
Empty DataFrame
Columns: [NYSE_close, NYSE_open, NYSE_volume, NASDAQ_close, NASDAQ_open, NASDAQ_volume]
Index: []