Tutorial by Topics: concatenate

DataFrame.merge(right, how='inner', on=None, left_on=None, right_on=None, left_index=False, right_index=False, sort=False, suffixes=('_x', '_y'), copy=True, indicator=False) Merge DataFrame objects by performing a database-style join operation by columns or indexes. If joining columns ...

If you are creating a dynamic string, It is a good practice to opt for StringBuilder class rather than joining strings using + or Concat method as each +/Concat creates a new string object everytime it is executed.