I have 2 dataframe as shown below
dff = pd.DataFrame([[0.4, 0.2, 0.4], [0.1, 0.3, 0.6], [0.3, 0.2, 0.5], [0.3,0.3,0.4]], columns=['WA', 'WB','WC'])
WA WB WC
0 0.4 0.2 0.4
1 0.1 0.3 0.6
2 0.3 0.2 0.5
3 0.3 0.3 0.4
dff2 = pd.DataFrame([[0.5, 0.2, 0.4]], columns = ['stv_A', 'stv_B', 'stv_c'])
stv_Astv_Bstv_c
0 0.5 0.2 0.4
Is there anyway to append dff2 which only consist of one row to every single row in ddf? Resulting dataframe should thus have 6 columns and rows
You can use:
dff[dff2.columns] = dff2.squeeze()
print(dff)
# Output
WA WB WC stv_A stv_B stv_c
0 0.4 0.2 0.4 0.5 0.2 0.4
1 0.1 0.3 0.6 0.5 0.2 0.4
2 0.3 0.2 0.5 0.5 0.2 0.4
3 0.3 0.3 0.4 0.5 0.2 0.4
Pandas does the broadcasting for you when you assign a scalar as a column:
import pandas as pd
dff = pd.DataFrame([[0.4, 0.2, 0.4], [0.1, 0.3, 0.6], [0.3, 0.2, 0.5], [0.3,0.3,0.4]], columns=['WA', 'WB','WC'])
dff2 = pd.DataFrame([[0.5, 0.2, 0.4]], columns = ['stv_A', 'stv_B', 'stv_c'])
for col in dff2.columns:
dff[col] = dff2[col][0] # Pass a scalar
print(dff)
Output:
WA WB WC stv_A stv_B stv_c
0 0.4 0.2 0.4 0.5 0.2 0.4
1 0.1 0.3 0.6 0.5 0.2 0.4
2 0.3 0.2 0.5 0.5 0.2 0.4
3 0.3 0.3 0.4 0.5 0.2 0.4
You can first repeat the row in dff2 len(dff) times with different methods, then concat the repeated dataframe to dff
df = pd.concat([dff, pd.concat([dff2]*len(dff)).reset_index(drop=True)], axis=1)
print(df)
WA WB WC stv_A stv_B stv_c
0 0.4 0.2 0.4 0.5 0.2 0.4
1 0.1 0.3 0.6 0.5 0.2 0.4
2 0.3 0.2 0.5 0.5 0.2 0.4
3 0.3 0.3 0.4 0.5 0.2 0.4
