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Creating binary variable depending on strings of two dataframes

4 messages · Pete Pete, Santosh Srinivas, Gabor Grothendieck +1 more

Pete Pete
# 
Hi,
consider the following two dataframes:
x1=c("232","3454","3455","342","13")
x2=c("1","1","1","0","0")
data1=data.frame(x1,x2)

y1=c("232","232","3454","3454","3455","342","13","13","13","13")
y2=c("E1","F3","F5","E1","E2","H4","F8","G3","E1","H2")
data2=data.frame(y1,y2)

I need a new column in dataframe data1 (x3), which is either 0 or 1
depending if the value "E1" in y2 of data2 is true while x1=y1. The result
of data1 should look like this:
   x1     x2 x3
1 232   1   1
2 3454 1   1
3 3455 1   0
4 342   0   0
5 13     0   1

I think a SQL command could help me but I am too inexperienced with it to
get there.

Thanks for your help!
Santosh Srinivas
# 
your question is not clear to me .. but your solution is a variation of
you can play with your conditions to get the result you want
On Tue, Dec 7, 2010 at 10:00 PM, Pete Pete <noxyport at gmail.com> wrote:
Gabor Grothendieck
#
On Tue, Dec 7, 2010 at 11:30 AM, Pete Pete <noxyport at gmail.com> wrote:
Try this:
x1 x2 x3
1  232  1  1
2 3454  1  1
3 3455  1  0
4  342  0  0
5   13  0  1
David Winsemius
#
On Dec 7, 2010, at 11:30 AM, Pete Pete wrote:

            

      
      
      
    

        
> dat3 <- merge(data1, data2[data2$y2=="E1", ], by.x="x1", by.y="y1",  
all.x=TRUE)
 > dat3$y2 <- 0 + (dat3$y2 %in% "E1")
 > dat3
     x1 x2 y2
1   13  0  1
2  232  1  1
3  342  0  0
4 3454  1  1
5 3455  1  0

(Admittedly not in the original order, but in my hands the R merge  
operation doesn't lend itself well to maintaining the original order.  
I see that Grothendieck's solution is better in this respect, a  
typical occurrence in comparison of our respective efforts with R.)