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If i have two data frames DF1 and DF2

> DF1
Date         EMMI      ACT      PM25
2011/02/12   12345     21       12
2011/02/14   14321     22       13
2011/02/19   12345     21       14
2011/02/24   14745     23       18

> DF2
Date         EMMI      ACT      NO2
2011/02/12   12345     21       11
2011/02/14   14321     22       12
2011/02/19   12345     21       13
2011/02/23   43211     13       12
2011/02/23   56341     13       12

Can anybody please let me know how to join these two data frames. by matching date and EMMI. So i want all similar dates and EMMI should be on the same rows. If they do not match then NAs should be present some thing like

> DF3
Date         EMMI      ACT      NO2   pm25
2011/02/12   12345     21       11    12
2011/02/14   14321     22       12    13
2011/02/19   12345     21       13    14
2011/02/23   43211     13       12    NA
2011/02/23   56341     13       12    NA
2011/02/24   14745     23       NA    18
flodel
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  • Yep, the answer (basically, use `merge()`) is pretty hard to miss with any search along the lines of "join dataframes" – alexwhan May 15 '13 at 02:21

0 Answers0