Selecting rows based on values in other table

Probably a beginner-question. I can't select a row based on criteria from other table. Should be simple, but I'm missing something.

I have two tables:

T1

X    C  
3    a  
4    a  
4开发者_C百科1   b

and

T2

A    B    C    D  
1    5    a   22  
7   11    a   27  
35  49    b   29 

I want to add the column D to T1, where X is between A and B in T2, and C=C. So the resulting table should look like this:

T1b

X    C    D  
3    a    22  
4    a    22  
41   b    29  

Thanks.

/Chris

This is one solution.

Import the data:

> con <- textConnection("X C
+ 3 a
+ 4 a
+ 41 b")
> T1 <- read.table(con, sep=" ", header=TRUE)
> close(con)

> con <- textConnection("A B C D
+ 1 5 a 22
+ 7 11 a 27
+ 35 49 b 29")
> T2 <- read.table(con, sep=" ", header=TRUE)
> close(con)

Now merge and subset:

> T3 <- merge(T1, T2)
> T3[T3$X > T3$A & T3$X < T3$B, c("X", "C", "D")]
   X C  D
1  3 a 22
3  4 a 22
5 41 b 29