R help - Apr 2012 - Merging multiple .csv files

Hi all,

I wish to merge 24 .csv files, each having a common identifier-column
("Name") and do two things:

1. Retrieve the common one's. [Analogy: while merging 2-dataframes, similar
to using: merge (.... ,by="Name", all=FALSE) ]

2. Retrieve all, i.e., the union of the rows of 24 files.  [again, somthing
like:  merge (.... ,by="Name", all=TRUE)  ]


On the web, I could see a few ways people seem to merge more than 2
dataframes.

I tried to use library (reshape), but it didn't bring any result:

 file_list <- list.files()
 m <- merge_all (file_list, by="Name")

Any help would be appreciated.

Thank you.

regards,
Chintanu

	[[alternative HTML version deleted]]

Your problem is that you can't merge the file names, but you need to
load them into R and merge the resulting objects.

This should be straightforward enough to do:

file_list <- list.files()
list_of_files <- lapply(file_list, read.csv) # Read in each file
merge_all(list_of_files, by = "Name")

Michael

On Wed, Apr 11, 2012 at 12:08 AM, Chintanu <chintanu at gmail.com>
wrote:
> Hi all,
>
> I wish to merge 24 .csv files, each having a common identifier-column
> ("Name") and do two things:
>
> 1. Retrieve the common one's. [Analogy: while merging 2-dataframes,
similar
> to using: merge (.... ,by="Name", all=FALSE) ]
>
> 2. Retrieve all, i.e., the union of the rows of 24 files. ?[again, somthing
> like: ?merge (.... ,by="Name", all=TRUE) ?]
>
>
> On the web, I could see a few ways people seem to merge more than 2
> dataframes.
>
> I tried to use library (reshape), but it didn't bring any result:
>
> ?file_list <- list.files()
> ?m <- merge_all (file_list, by="Name")
>
> Any help would be appreciated.
>
> Thank you.
>
> regards,
> Chintanu
>
> ? ? ? ?[[alternative HTML version deleted]]
>
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