PythonTitus PythonTitus - 3 months ago 11
Python Question

merge two dataframes by row with same index pandas

let's say i have the following two dataframes X1 and X2. I would like
to merge those 2 dataframes by row so that each index from each
dataframe being the same combines the corresponding rows from both
dataframes.

A B C D
DATE1 a1 b1 c1 d1

DATE2 a2 b2 c2 d2

DATE3 a3 b3 c3 d3


A B C D
DATE1 f1 g1 h1 i1

DATE2 f2 g2 h2 i2

DATE3 f3 g3 h3 i3

how would i combine them to get


A B C D
DATE1 A1 B1 C1 D1
f1 g1 h1 i1

DATE2 A2 B2 C2 D2
f2 g2 h2 i2

DATE3 A3 B3 C3 D3
f3 g3 h3 i3


I have tried this so far but this does not seem to work:

d= pd.concat( { idx : [ X1[idx], tickerPortfolio[idx], X2[idx]] for idx, value in appended_data1.iterrows() } , axis =1}


thanks

Answer
df3 = df1.stack().to_frame('df1')
df3.loc[:, 'df2'] = df2.stack().values
df3 = df3.stack().unstack(1)
df3

enter image description here


Setup

from StringIO import StringIO
import pandas as pd


df1_text = """       A  B C  D
DATE1 a1 b1 c1 d1
DATE2 a2 b2 c2 d2
DATE3 a3 b3 c3 d3"""


df2_text = """       F  G H  I
DATE1 f1 g1 h1 i1
DATE2 f2 g2 h2 i2
DATE3 f3 g3 h3 i3"""

df1 = pd.read_csv(StringIO(df1_text), delim_whitespace=True)
df2 = pd.read_csv(StringIO(df2_text), delim_whitespace=True)

df1

enter image description here

df2

enter image description here