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

[Adaikalavan Ramasamy]

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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