Pandas Merge returns NaN

Question

I have issues with the merging of two large Dataframes since the merge returns NaN values though there are fitting values. The two dfs are shaped like:

df1

Answer 1

Spent 2-3 hours trying to resolve this issue. Didn't rcv any error message but just NaN. Dtypes was the issue.

Answer 2

You need same dtype of joined columns:

#convert first or second to str or int
MergeDat['Motor'] = MergeDat['Motor'].astype(str)
#Motor['Motor'] = Motor['Motor'].astype(str)

#MergeDat['Motor'] = MergeDat['Motor'].astype(int)
Motor['Motor'] = Motor['Motor'].astype(int)

---

#convert first or second to str or int
#MergeDat['Motor'] = MergeDat['Motor'].astype(str)
Motor['Motor'] = Motor['Motor'].astype(str)

MergeDat['Motor'] = MergeDat['Motor'].astype(int)
#Motor['Motor'] = Motor['Motor'].astype(int)


MergeDat=MergeDat.merge(Motor,how="left")