assign a column with a column of another df

  AI, Pandas, Python 

df2['date'] = df1['date'].values
df2['hour'] = df1['hour'].values

It’s better use inter join

case.tail(3)
	       caseCA	caseON caseDaily CAcaseDailyON
case_Date_province				
2020-04-26	47864	15411	1598.0	498.0
2020-04-27	49499	15868	1635.0	457.0
2020-04-28	50982	16337	1483.0	469.0

test.tail(3)
                testCA	testON	testDailyCA testDailyON
date_testing				
2020-04-26	734824	229638	23570.0	12020.0
2020-04-27	765056	242188	30232.0	12550.0
2020-04-28	787612	253040	22556.0	10852.0


case_test = pd.concat([case, test], axis=1, join='inner')

case_test.tail(5)
	caseCA	caseON	caseDailyCA	caseDailyON	testCA	testON	testDailyCA	testDailyON	ratioCA	ratioON	ratioDailyCA	ratioDailyON
2020-04-26	47864	15411	1598.0	498.0	734824	229638	23570.0	12020.0	6.513669	6.710997	6.779805	4.143095
2020-04-27	49499	15868	1635.0	457.0	765056	242188	30232.0	12550.0	6.469984	6.551935	5.408177	3.641434
2020-04-28	50982	16337	1483.0	469.0	787612	253040	22556.0	10852.0	6.472984	6.456291	6.574747	4.321784