How To Merge A Multirows Header Of A Pandas Dataframe Into A Single Cell Header?

I have a pandas DataFrame from an excel file with the header split in multiple rows as the following example: 0 1 2 3 4 5 6

Solution 1:

You can first select by loc, then replace NaN to empty string by fillna and apply join. If necessary remove first and last whitespaces by str.strip and then remove first rows by selecting df.loc[10:]:

df.columns = df.loc[5:9].fillna('').apply(' '.join).str.strip()

#if need monotonic index (0,1,2...) add reset index
print (df.loc[10:].reset_index(drop=True))
  Planting date YYYY.DDD Harvest date YYYY.DDD(kg/ha) Yield YYYY.DDD  \
0                1999.26                      2000.21        5669.46   
1                2000.27                      2001.22        10282.5   
2                2001.27                      2002.22        8210.09   

  Flowering date YYYY.DDD Maturity date YYYY.DDD Maturity date YYYY.DDD  \
0                 2000.14                2000.19                2000.19   
1                 2001.15                 2001.2                 2001.2   
2                 2002.15                 2002.2                 2002.2   

  Maturity date (kg/ha) Above ground biomass  
0               2000.19              11626.7  
1                2001.2                20565  
2                2002.2                16509