Concatenate/Join/Merge two Dataframes

[karlito]

Totally unclear for me what data you have and how you want to manipulate it.

Want to add column to existing dataframe?

>>> df = pd.DataFrame({'nums': range(5)})                            
>>> df                                                               
   nums
0     0
1     1
2     2
3     3
4     4
>>> df['chars'] = list('abcde')                                      
>>> df                                                               
   nums chars
0     0     a
1     1     b
2     2     c
3     3     d
4     4     e
>>> df['NaNs'] = np.nan                                              
>>> df                                                               
   nums chars  NaNs
0     0     a   NaN
1     1     b   NaN
2     2     c   NaN
3     3     d   NaN
4     4     e   NaN

Hi,

I have two Dataframes.
- test_df with 2 columns: date as index and night_cons (see image)
- pred_df with just a column "prediction" (see image)

I'm trying to merge both but when I do it, the final merged Dataframe gives NAN in the prediction column (see image please)

---

Hi,
I got it ... It was an index issue.
Thank you all.