如何重新标记连接到现有数据框的一些新计算的列？

Posted 2023-03-11

【中文标题】如何重新标记连接到现有数据框的一些新计算的列？

【英文标题】：How to relabel some newly calculated columns that were concatenated to an existing dataframe?

【发布时间】：2021-06-24 04:24:34

【问题描述】：

我的目标是重新标记我连接到现有数据框的一些新计算的列。

简而言之，我有以下步骤：

一个。我从雅虎财经图书馆（a 235 x 28) 乙。然后我计算了对数返回 (235 x 4) 并连接 他们 c。创建了新标签 d.如何新替换 b 的标签 添加了列？

我的问题是如何执行步骤 d？ （见下面的代码）

# Install yfinance and matplotlib package
!pip install yfinance
!pip install matplotlib

# Import yfinance and matplotlib
import yfinance as yf  
import matplotlib.pyplot as plt

# list of interesting stocks, ETFs by ticker
slist = ['SPY', 'AAPL', 'QQQ', 'AMZN']

# step a: Get the data for list of stocks specified by s plus start date, and end date
df = yf.download(slist,'2020-01-01','2020-12-06')
print(df)
print(df.shape)

# step b: concatenate the Log Returns onto the existing df
df = pd.concat([df, np.log(df['Adj Close']/df['Adj Close'].shift(1)).dropna()], axis = 1)
print(df)
print(df.shape)

# one can see that the concatenated columns don't have the appropriate header labels yet
# they just have the name of the tickers in slist
df.head().iloc[ :, -len(slist):]

# step c: create new labels where it becomes ticker + ' Log Rtn' and try to use these
slabel = [s + ' Log Rtn' for s in slist]
print(slabel)

# step d: Here I would like to rename the headers of the part that was added to dataframe, df, such that it uses (slabel)

# show correct end results hopefully
df.head().iloc[ :, -len(slist):]

【参考方案1】：

如果新列标题的名称来自slist；那么这应该可以工作。

slist = ['SPY', 'AAPL', 'QQQ', 'AMZN']
for prev_hd, new_hd in zip(slist, slabel):
    df = df.rename(columns=prev_hd: new_hd)

更一般的

df = df.rename(columns='oldName1': 'newName1', 'oldName2': 'newName2')