pandas 合并数据框列表以创建一个数据框

Merge a list of dataframes to create one dataframe

提问by Josh

I have a list of 18 data frames:

我有一个包含 18 个数据框的列表：

dfList = [df1, df2, df3, df4, df5, df6.....df18]

All of the data frames have a common id column so it's easy to join them each together with pd.merge 2 at a time. Is there a way to join them all at once so that dfList comes back as a single dataframe?

所有的数据框都有一个共同的 id 列，因此很容易一次将它们与 pd.merge 2 连接在一起。有没有办法一次将它们全部加入，以便 dfList 作为单个数据帧返回？

回答by jezrael

I think you need concat, but first set index of each DataFrameby common column:

我认为您需要concat，但首先DataFrame按公共列设置每个索引：

dfs = [df.set_index('id') for df in dfList]
print pd.concat(dfs, axis=1)

If need join by merge:

如果需要加入merge：

df = reduce(lambda df1,df2: pd.merge(df1,df2,on='id'), dfList)