[R] merge multiple .csv files

[Erik Iverson]

On 02/09/2011 09:21 PM, Benjamin Caldwell wrote:
> Am trying to merge about 15 .csv tables - tried a test run but came up with
> 0 rows (no data for each variable/column head)
>
>> CAHSEE.EA.feb.2009<-read.csv("2009 CAHSEE EA feb 2009.csv", header=TRUE)
>> CAHSEE.IM.MATH.2009<-read.csv("2009 CAHSEE Impact Math.csv", header=TRUE)
>> testmerge<-merge(CAHSEE.EA.feb.2009,CAHSEE.IM.MATH.2009)
>> testmerge
>   [1] Grade          LocalStudentID MathPassed     MathScaleScore SchoolCode
>
>   [6] LastName       FirstName      ELAPassed      ELAScaleScore
>   MathTestDate
> <0 rows>  (or 0-length row.names)
>
> I know several variables are shared in both sheets. Please advise.

Please provide a reproducible example, otherwise we have no idea what
your objects that are giving you trouble look like.  You can use the
?dput function to facilitate this.

In general, I end up with your situation when I have data that differ
between the common names in the two data.frames. You might try the "by"
argument in merge...

Best.
--Erik