How do I merge two data frames on one column if the column has a different name in each dataset?

Question

I have two dataframes df1 and df2. df1 has column "ID" while df2 has column "ID_NUMBER".

Here's df1 in comma separated format:

ID, ANIMAL
1, dog
2, alligator
4, cat
5, cougar

And df2

ID_NUMBER, WEIGHT
1, 100
2, 1000
3, 12
5, 125

How do I merge these two datasets on df1$ID/df2$ID_NUMBER, keeping only the rows where they have the ID number in common?

You can try `merge(df1, df2, by.x = 'ID', by.y = 'ID_NUMBER')` — Gopala, Apr 12 '16 at 21:24
@Gopala My apologies. I updated my question to better reflect my dataset. — Username, Apr 12 '16 at 21:29
@Gopala I read them in from separate .CSV files, if that's what you mean — Username, Apr 12 '16 at 21:34
If you already have those data frames, the command I gave you should work. What part of it is not working? — Gopala, Apr 12 '16 at 21:38

score 2 · Accepted Answer · answered Apr 12 '16 at 21:39

Here is the output. Is this not what you want?

df1 <- read.table(text = 'ID, ANIMAL
                          1, dog
                          2, alligator
                          4, cat
                          5, cougar', header = TRUE)
df1
df2 <- read.table(text = 'ID_NUMBER, WEIGHT
                          1, 100
                          2, 1000
                          3, 12
                          5, 125', header = TRUE)
df2
merge(df1, df2, by.x = 'ID.', by.y = 'ID_NUMBER.')
  ID.    ANIMAL WEIGHT
1  1,       dog    100
2  2, alligator   1000
3  5,    cougar    125

How do I merge two data frames on one column if the column has a different name in each dataset?

1 Answers1