I think, but I'm not sure, that when you use merge it basically attaches one data frame to the other. I do not think it matches up entries from a particular column in each data frame (and I know biologists frequently want to match entries from a particular column in each data frame). For that, I think you need a join from the dplyr package.

   If you do a right join, then it will use only the entries from the second df (the data frame to the right, df1). Entries in df, that are not in df1 will not be in the final (in your example the final is df). So, from you code, you took df and then joined it to where it had entries in df1 and changed df to contain only entries in df that were in df1. Had you done a left_join, then your final data frame, df, would contain only those entries found originally in df and df1 (entries in df1, but not in df would be excluded in the final df).

   You could do a full_join and then all entries (entries in both data frames, entries in df but not in df1, and entries in df1 but not in df) will be in the final. Maybe something like : (In this case I have created a new data frame, df_final, but you could still go with just changing df.)

df_final<- full_join(df, df1, by = c(“Sample”, "Plot"))

Matthew


On 6/29/21 7:15 PM, Jim Lemon wrote:
         External Email - Use Caution

Hi Esthi,
Have you tried something like:

df2<-merge(df,df1,by.x="Sample",by.y="Plot",all.y=TRUE)

This will get you a right join in "df2", not overwriting "df".

Jim

On Wed, Jun 30, 2021 at 1:13 AM Esthi Erickson <ericksones...@gmail.com> wrote:
Hi and thank you in advance,

If I have a dataframe, df:

Sample

Plot

Biomass

1

1

1024

1

2

32

2

3

223

2

4

456

3

1


3

2

331

3

3

22151

3

4

1441

And another one, df1:

Sample

Plot

% cover of plant1

% cover of plant2

3

1

32

63

3

2

3


3

3


3

3

4

5

23

I want to join these tables where the columns Sample and Plot are the same.

Currently trying:

df<- right_join(df, df1, by = c(“Sample”, "Plot"))

I am working with a much larger dataset, but it will cut off the data
starting at Sample 3 instead of joining the tables while retaining the
information from df. Any ideas how I could join them this way?


Esthi

         [[alternative HTML version deleted]]

______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://secure-web.cisco.com/1NdijE3bwtTnJ0kSEgtJU1NlrtOK9zEfac9zyeZv87EuBW5RBFz3d1rdtVoxuWjjEZm2ILfmP1KOs1kEsAOECi2THQ-_HKB9EOJWeI57gQdy8H3UbdNo5_jjkMLPJ7OWuokUT-FJwD84kR0uptsG7XUn_xN9NkAZ4ESV6jXCMs_vWVuqkvXkPRfDV0BBMBQWLKxiQKz-9GYTrcqzWGsCc_A1LB3p6YBnMcOeElnau9pAicwrSrzqbNayjDWgW75J91dn1Bpb7rhV4xLELl_KS0g/https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help
PLEASE do read the posting guide 
http://secure-web.cisco.com/1yHZkzpQUOKRg8cDG22MQDxPOC13uXEOgchugGyn3LgrkzeHEY3bJmUM7BdgniFNPIUlVK9c26rAxELBoKzCk3QtR375fxo8PTFptWSOByZg9wWZw8ounbb3NvkgZApJHaDn6KCFRf4ym05BIQUG039oUDbsdBh6fa5LNBsdgTIGVetQokelOMdncVxIv_g233z1CF1xfAozJ9-8eetgqhSIh1lRMlheHhpVRDzkSbxAij8APSko49XhpHmsqwOevGN0c3vHgLT2dLLAzvO_ZLA/http%3A%2F%2Fwww.R-project.org%2Fposting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://secure-web.cisco.com/1NdijE3bwtTnJ0kSEgtJU1NlrtOK9zEfac9zyeZv87EuBW5RBFz3d1rdtVoxuWjjEZm2ILfmP1KOs1kEsAOECi2THQ-_HKB9EOJWeI57gQdy8H3UbdNo5_jjkMLPJ7OWuokUT-FJwD84kR0uptsG7XUn_xN9NkAZ4ESV6jXCMs_vWVuqkvXkPRfDV0BBMBQWLKxiQKz-9GYTrcqzWGsCc_A1LB3p6YBnMcOeElnau9pAicwrSrzqbNayjDWgW75J91dn1Bpb7rhV4xLELl_KS0g/https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help
PLEASE do read the posting guide 
http://secure-web.cisco.com/1yHZkzpQUOKRg8cDG22MQDxPOC13uXEOgchugGyn3LgrkzeHEY3bJmUM7BdgniFNPIUlVK9c26rAxELBoKzCk3QtR375fxo8PTFptWSOByZg9wWZw8ounbb3NvkgZApJHaDn6KCFRf4ym05BIQUG039oUDbsdBh6fa5LNBsdgTIGVetQokelOMdncVxIv_g233z1CF1xfAozJ9-8eetgqhSIh1lRMlheHhpVRDzkSbxAij8APSko49XhpHmsqwOevGN0c3vHgLT2dLLAzvO_ZLA/http%3A%2F%2Fwww.R-project.org%2Fposting-guide.html
and provide commented, minimal, self-contained, reproducible code.

______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Reply via email to