How to add a column from one dataframe to another dataframe when two other columns match [duplicate] - r

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This question already has answers here:
How to join (merge) data frames (inner, outer, left, right)
(13 answers)
Closed 3 years ago.
I have two datasets, db1 and db2, like the following ones:
db1
+---------+-------+-------+------+------+-----------------+
| Authors| IDs | Title | Year | ISSN | Other columns...|
+---------+-------+-------+------+------+-----------------+
| Abad J.| 16400 | 1 | 2014 |14589 | |
| Ares K.| 70058 | 2 | 2012 |15874 | |
| Anto E.| 71030 | 3 | 2011 |16999 | |
| A Banul| 57196 | 1 | 2011 |21546 | |
| A Berat| 56372 | 2 | 2011 |12554 | |
+---------+-------+-------+------+------+-----------------+
and
db2
+---------+-------+-------+------+------+-------+---------------------------+
| Authors| IDs | Title | Year | ISSN | IF | Other different columns...|
+---------+-------+-------+------+------+-------+---------------------------+
| Abad J.| 16400 | 1 | 2013 |14589 | 2,3 | |
| Ares K.| 70058 | 2 | 2012 |15874 | 3,3 | |
| Anto E.| 71030 | 3 | 2011 |14587 | 1,2 | |
| A Banul| 57196 | 1 | 2011 |21546 | 7,8 | |
| A Berat| 56372 | 2 | 2011 |75846 | 4,5 | |
+---------+-------+-------+------+------+-------+---------------------------+
Basically, what i want is to add to db1 the column IF from db2 when the two columns Year and ISSN have the same values. So what i want to achive is the following output in my example:
db1
+---------+-------+-------+------+------+-------+----------------+
| Authors| IDs | Title | Year | ISSN | IF |Other columns...|
+---------+-------+-------+------+------+-------+----------------+
| Abad J.| 16400 | 1 | 2014 |14589 | NA | |
| Ares K.| 70058 | 2 | 2012 |15874 | 3,3 | |
| Anto E.| 71030 | 3 | 2011 |16999 | NA | |
| A Banul| 57196 | 1 | 2011 |21546 | 7,8 | |
| A Berat| 56372 | 2 | 2011 |12554 | NA | |
+---------+-------+-------+------+------+-------+----------------+
i have tried with merge but, since i have also different columns, i obtain a very big dataset.
What i want is to use the function match but with more than one condition applied at the same time.
Any guess ?

Answer 1

dplyr::left_join(db1, db2 %>% dplyr::select(Year, ISSN, IF))
This should work providing the two dataframes have no other columns in common besides the ones you've shown here.