combine like columns in dataframe pandas code example

Example 1: concact geodataframe python

>>> s1 = pd.Series(['a', 'b'])
>>> s2 = pd.Series(['c', 'd'])
>>> pd.concat([s1, s2])
0    a
1    b
0    c
1    d
dtype: object

Example 2: combine df columns python

df["period"] = df["Year"] + df["quarter"]