join_data

# Description:
# join data from other dataframe
# used methods '.assign' and '.explode' (for melt),
# and '.merge' (for join)

import pandas as pd

df1 = pd.DataFrame([[0, 'text1', 'value1, value2'],
                    [1, 'text2', 'value3, value4'],
                    [2, 'text3', 'value5, value6']])
df1.columns = ['cnt', 'text', 'values']
# print(df1)

df2 = pd.DataFrame([[0, 'value1', 'Moscow'],
                    [1, 'value2', 'Tokyo'],
                    [2, 'value3', 'London'],
                    [3, 'value4', 'Berlin'],
                    [4, 'value5', 'Las Vegas'],
                    [5, 'value6', 'Rio de Janeiro']])
df2.columns = ['indx', 'code_value', 'data']
# print(df2)

df1 = df1.assign(code_value=df1['values'].str.split(', '))
df1 = df1.explode('code_value')
df1 = pd.merge(df1, df2, how='left', on='code_value')
df1 = df1.drop('indx', axis=1)
df1