按预定义列串联/合并数据框列表 [英] Concatenating/Merging List of Dataframes by Predefined columns
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问题描述
我有以下数据帧列表:
import pandas as pd
rep1 = pd.DataFrame.from_items([('Probe', ['x', 'y', 'z']), ('Gene', ['foo', 'bar', 'qux']), ('RP1',[1.00,23.22,11.12])], orient='columns')
rep2 = pd.DataFrame.from_items([('Probe', ['x', 'y', 'z']), ('Gene', ['foo', 'bar', 'qux']), ('RP2',[11.33,31.25,22.12])], orient='columns')
rep3 = pd.DataFrame.from_items([('Probe', ['x', 'y', 'z']), ('Gene', ['foo', 'bar', 'qux'])], orient='columns')
tmp = []
tmp.append(rep1)
tmp.append(rep2)
tmp.append(rep3)
# In actuality the DF could be more than 3.
哪个会产生:
In [53]: tmp
Out[53]:
[ Probe Gene RP1
0 x foo 1.00
1 y bar 23.22
2 z qux 11.12, Probe Gene RP2
0 x foo 11.33
1 y bar 31.25
2 z qux 22.12, Probe Gene
0 x foo
1 y bar
2 z qux]
我想要做的是连接该数据帧列表,以便得到以下结果:
What I want to do is to concatenate that list of dataframes so that it results in this:
Probe Gene RP1 RP2
0 x foo 1.00 11.33
1 y bar 23.22 31.25
2 z qux 11.12 22.12
请注意,rep3
仅包含两列.在连接的过程中,我们希望将其自动丢弃.
Note that rep3
only contain two columns. In the process of concatenating, we hope to automatically discard it.
我尝试使用此代码,但无济于事.正确的方法是什么?
I tried with this code but no avail. What's the right way to do it?
In [57]: full_df = pd.concat(tmp,axis=1).fillna(0)
In [58]: full_df
Out[58]:
Probe Gene RP1 Probe Gene RP2 Probe Gene
0 x foo 1.00 x foo 11.33 x foo
1 y bar 23.22 y bar 31.25 y bar
2 z qux 11.12 z qux 22.12 z qux
推荐答案
我不确定这是否是正确的方法,但是一种整洁的方法是使用减少:
I'm not sure this is the right way to do this, but a kind-of neat way is to use reduce:
In [11]: reduce(pd.merge, tmp)
Out[11]:
Probe Gene RP1 RP2
0 x foo 1.00 11.33
1 y bar 23.22 31.25
2 z qux 11.12 22.12
这基本上等同于:
This is basically equivalent to:
tmp[0].merge(tmp[1]).merge(tmp[2])...
注意:这意味着如果tmp中有很多DataFrame,它的效率可能不如concat.
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