[R] Matching

[Doran, Harold]

You don't need grep for this. Use the merge() function and make sure the
arguments all.x and all.y are considered depending on whether this is a
left or right merge. 

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of vpas
> Sent: Monday, December 22, 2008 11:03 AM
> To: r-help at r-project.org
> Subject: [R] Matching
> 
> 
> I understand this is an easy question, and have been playing 
> around with grep and the match function, but was hoping for a 
> little incite:
> 
> I have one .csv with the following data:
> 
> names values
> A        1
> B        2
> C        3
> D        4
> 
> 
> The second .csv is:
> 
> names
> A
> C
> 
> 
> I am hoping to match all of the rows that appear in the 
> second .csv, making a new file that would look like this:
> 
> names values
> A        1
> C        3
> 
> 
> Here is what I have so far:
> 
> my.data <- read.csv("rows.csv",sep=",")
> my.selection <- read.csv("select.csv",sep=",") matched <- 
> match(my.data[,1], my.selection[,1]) my.data <- 
> my.data[matched] write.table(as.matrix(my.data), "select_RESULTS.txt")
> 
> Unfortunately, this is throwing errors in row numbers...  
> 
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