R help - May 2007 - Get the difference between two matrices with different length

Hello,
I have got two matrices with different length. The matrices have 3
columuns. The first two are coordinates. The third is a measurement.

Now I want to get a subtraction between every single value of the 
third column (between matrix1 and matrix2), but only if the two 
first coordinates in matrix1 and matrix2 are the same.

I tried "FUN=?" in aggregate and ave, but I don't know the command
for such a subtraction?


Thank's a lot.
Felix


---------------

The matrixes (examlple):

1 0.1 0.0042
1 0.2 0.00423
1 0.4 0.00467
1 0.5 0.00518
1 0.6 0.0061


1 0.1 0.0043
1 0.2 0.00442
1 0.3 0.00433
1 0.4 0.0045
1 0.5 0.00524
1 0.7 0.006



My aim:
-------
1 0.1 -0.0001
1 0.2 -0.00019
1 0.4 0.00017
1 0.5 -0.00006

try this:

ind1 <- do.call("paste", c(as.data.frame(mat1[, 1:2]), sep =
"\r"))
ind2 <- do.call("paste", c(as.data.frame(mat2[, 1:2]), sep =
"\r"))
mat1[ind1 %in% ind2, 3] - mat2[ind2 %in% ind1, 3]


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Felix Wave" <felix-wave at vr-web.de>
To: <r-help at stat.math.ethz.ch>
Sent: Friday, May 04, 2007 1:26 PM
Subject: [R] Get the difference between two matrices with different 
length

> Hello,
> I have got two matrices with different length. The matrices have 3
> columuns. The first two are coordinates. The third is a measurement.
>
> Now I want to get a subtraction between every single value of the
> third column (between matrix1 and matrix2), but only if the two
> first coordinates in matrix1 and matrix2 are the same.
>
> I tried "FUN=?" in aggregate and ave, but I don't know the
command
> for such a subtraction?
>
>
> Thank's a lot.
> Felix
>
>
> ---------------
>
> The matrixes (examlple):
>
> 1 0.1 0.0042
> 1 0.2 0.00423
> 1 0.4 0.00467
> 1 0.5 0.00518
> 1 0.6 0.0061
>
>
> 1 0.1 0.0043
> 1 0.2 0.00442
> 1 0.3 0.00433
> 1 0.4 0.0045
> 1 0.5 0.00524
> 1 0.7 0.006
>
>
>
> My aim:
> -------
> 1 0.1 -0.0001
> 1 0.2 -0.00019
> 1 0.4 0.00017
> 1 0.5 -0.00006
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 

Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

Hello,

The answer is in one page of the R Wiki (just created to address such a 
question, by the way): 
http://wiki.r-project.org/rwiki/doku.php?id=tips:data-manip:calc_on_two_tables

..............................................<?}))><........
  ) ) ) ) )
( ( ( ( (    Prof. Philippe Grosjean
  ) ) ) ) )
( ( ( ( (    Numerical Ecology of Aquatic Systems
  ) ) ) ) )   Mons-Hainaut University, Belgium
( ( ( ( (
..............................................................

Felix Wave wrote:
> Hello,
> I have got two matrices with different length. The matrices have 3
> columuns. The first two are coordinates. The third is a measurement.
> 
> Now I want to get a subtraction between every single value of the 
> third column (between matrix1 and matrix2), but only if the two 
> first coordinates in matrix1 and matrix2 are the same.
> 
> I tried "FUN=?" in aggregate and ave, but I don't know the
command
> for such a subtraction?
> 
> 
> Thank's a lot.
> Felix
> 
> 
> ---------------
> 
> The matrixes (examlple):
> 
> 1 0.1 0.0042
> 1 0.2 0.00423
> 1 0.4 0.00467
> 1 0.5 0.00518
> 1 0.6 0.0061
> 
> 
> 1 0.1 0.0043
> 1 0.2 0.00442
> 1 0.3 0.00433
> 1 0.4 0.0045
> 1 0.5 0.00524
> 1 0.7 0.006
> 
> 
> 
> My aim:
> -------
> 1 0.1 -0.0001
> 1 0.2 -0.00019
> 1 0.4 0.00017
> 1 0.5 -0.00006
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>