cpd.concat code example
Example 1: concat pandas 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: pandas concat and reset index
train_df = pd.concat(train_class_df_list, ignore_index=True)