Creating binary variable depending on strings of two dataframes
On Tue, Dec 7, 2010 at 11:30 AM, Pete Pete <noxyport at gmail.com> wrote:
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.
Try this:
library(sqldf)
sqldf("select x1, x2, max(y2 = 'E1') x3 from data1 d1 left join data2 d2 on (x1 = y1) group by x1, x2 order by d1.rowid")
x1 x2 x3 1 232 1 1 2 3454 1 1 3 3455 1 0 4 342 0 0 5 13 0 1
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