[R] filling columns in frame according to another column frame

[Adaikalavan Ramasamy]

So you want to grep for each pattern as indicated by columns of test2 in
the columns of test1. Something like your initial approach.

 p <- c(1,3,5)      # pattern like test2$'cm'
 x <- sample(1:10)  # data    like test1$'cm'

 x
 [1]  3  4  9  8  7  5 10  2  1  6

 x %in% p
 [1]  TRUE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE

 (w <- which( x %in% p ))
[1] 1 6 9

If no matches are found, you get numeric(0) for 'w' and I usually test
this using length(w)==0. 


On second thought, I tried your original solution and it appears to work
but not tested thoroughly. Can you provide a _simple_ example where this
does not work. Thank you.

 z <- 1:length(x)             # like test1$'3'
 z
 [1]  1  2  3  4  5  6  7  8  9 10

 ifelse( x %in% p, z, 0 )
 [1] 1 0 0 0 0 6 0 0 9 0


BTW, why are you quoting your names as in 'cm' and '3' and are test1,
test2 really data.frames ? What does class(test1) and class(test1$'cm')
say ?

Regards, Adai


On Wed, 2005-02-23 at 15:38 +0000, Luis Ridao Cruz wrote:
> I think I did not explain very well what my problem is,
> 
> Both frames have the same number of columns but different number of
> rows.
> The point is to compare 'cm' column in test1 with 'cm' in test2 as
> follows
> 
> first element in test2$'cm'  versus first element in test1$'cm' 
> first element in test2$'cm'  versus second element in test1$'cm' 
> first element in test2$'cm'  versus element element in test1$'cm'
> .....
> 
> 
> if any of the above matches returns the value in column , lets say 10,
> of  element in test1$'cm' , if not then 0
> 
> Luis
> 
> 
> >>> Adaikalavan Ramasamy <ramasamy at cancer.org.uk> 23/02/2005 15:07:55
> >>>
> I am confused. Are you saying that your two data frames are of
> different
> dimensions ? 
> 
> In any case what I think what you are looking for is which.
> 
> # generate the conditioning matrix
> a <- matrix( sample(0:1, 9, replace=TRUE), nc=3 )
> a
>      [,1] [,2] [,3]
> [1,]    1    1    1
> [2,]    1    0    0
> [3,]    0    0    1
> 
> # find the index where zero is present
> ( w <- which( a == 0, arr.ind=T ) )
>      row col
> [1,]   3   1
> [2,]   2   2
> [3,]   3   2
> [4,]   2   3
> 
> # generate the matrix of interest
> ( b <- matrix(1:9, nc=3, byrow=T) )
>      [,1] [,2] [,3]
> [1,]    1    2    3
> [2,]    4    5    6
> [3,]    7    8    9
> 
> # values that will be used to impute the zero's in a
> b[w]
> [1] 7 5 8 6
> 
> # impute the values of a with b where a is zero
> a[w] <- b[w]
> 
> # the result
> a
>      [,1] [,2] [,3]
> [1,]    1    1    1
> [2,]    1    5    6
> [3,]    7    8    1
> 
> 
> Regards, Adai
> 
> 
> On Wed,	 2005-02-23 at 14:14 +0000, Luis Ridao Cruz wrote:
> > R-help,
> > 
> > I have a frame which I want to fill up conditioning to another data
> > frame column.
> > 
> > The one I want to fill up is as follows (basically an empty one):
> > 
> > > test2
> > 
> >      cm 0   1   2   3   4   5   6   7   8   9  10  11 12 13 14 15
> >      1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1  
> 1
> >      2   2   2   2   2   2   2   2   2   2   2   2   2   2   2   2  
> 2
> >      3   3   3   3   3   3   3   3   3   3   3   3   3   3   3   3  
> 3
> >      4   4   4   4   4   4   4   4   4   4   4   4   4   4   4   4  
> 4
> >      5   5   5   5   5   5   5   5   5   5   5   5   5   5   5   5  
> 5
> >      6   6   6   6   6   6   6   6   6   6   6   6   6   6   6   6  
> 6
> >      7   7   7   7   7   7   7   7   7   7   7   7   7   7   7   7  
> 7
> >      8   8   8   8   8   8   8   8   8   8   8   8   8   8   8   8  
> 8
> >      9   9   9   9   9   9   9   9   9   9   9   9   9   9   9   9  
> 9
> > 
> > The other looks like :
> > 
> > > test1
> > 
> >    cm 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
> >    38 0 0 1 0 0 0 6 0 0 0  0  0  0  0  0  0
> >    39 0 0 1 0 0 0 0 0 0 0  0  0  6  0  0  0
> >    40 0 0 1 0 0 0 0 0 0 0  0  0  0  0  0  0
> >    41 0 0 2 0 0 0 0 0 0 0  6  0  0  0  0  0
> >    43 0 0 1 0 0 0 4 0 0 0  0  0  0  0  0  0
> >    44 0 0 4 0 0 0 5 0 0 0  0  0  0  0  0  0
> >    45 0 0 2 0 0 0 0 0 0 0  6  0  0  0  0  0
> >    47 0 0 3 0 0 0 0 0 0 0  0  0  0  0  0  0
> >    48 0 0 2 0 0 0 0 0 0 6  0  0  0  0  0  0
> >    49 0 0 2 0 0 0 0 0 0 6  0  0  0  0  0  0
> >    50 0 0 3 0 0 0 0 0 0 3  0  0  0  0  0  0
> >    51 0 0 2 0 0 0 0 0 0 3  0  0  0  0  0  0
> > 
> > Length of both frames are different ( test2 = 150 and test1 = 70 )
> > The key column is 'cm'
> > 
> > I have tried someting (fill column '3' in test2):
> > 
> > test2 [, '3' ]<-
> > ifelse ( test2$'cm'  %in% test1$'cm' , test1$'3' , 0)
> > 
> > but the result is wrong.
> > 
> > Any suggestions?
> > 
> > Thanks in advance
> > 
> > 
> > > version
> >          _              
> > platform i386-pc-mingw32
> > arch     i386           
> > os       mingw32        
> > system   i386, mingw32  
> > status                  
> > major    2              
> > minor    0.1            
> > year     2004           
> > month    11             
> > day      15             
> > language R
> > 
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> > 
> 
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