keep dimension of a sub matrix

See

 > help("[")

which informs you about the additional argument "drop":

 > ret <-matrix(1,4,4)[i1:i2,j1:j2,drop=FALSE] ;

BTW, you do not need to end lines of code with a ";" ...

Eric

Hi,
is there any way to keep a sub matrix dimension?

exemple :
i1<-1; i2<-1
j1<-2; j2<-3;
ret <-matrix(1,4,4)[i1:i2,j1:j2] ;

dim(ret) is NULL because the submatrix single col or single row is coerce 
to a vector automaticaly.
How can i bypass this cast  : submatrix->vector   ???????

Thank you.





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




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If the statistics are boring, then you've got the wrong numbers. -Edward 
Tufte

just use

matrix(1,4,4)[i1:i2,j1:j2, drop=FALSE]

Best,
Dimitris

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

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/396887
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "JC Vaugeois" <vaugeoisjc at yahoo.fr>
To: <R-help at stat.math.ethz.ch>
Sent: Thursday, November 04, 2004 12:06 PM
Subject: [R] keep dimension of a sub matrix


Hi,
is there any way to keep a sub matrix dimension?

exemple :
i1<-1; i2<-1
j1<-2; j2<-3;
ret <-matrix(1,4,4)[i1:i2,j1:j2] ;

dim(ret) is NULL because the submatrix single col or single row is 
coerce to a vector automaticaly.
How can i bypass this cast  : submatrix->vector   ???????

Thank you.





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


______________________________________________
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

JC Vaugeois <vaugeoisjc at yahoo.fr> writes:

Hi,
is there any way to keep a sub matrix dimension?
 
exemple :
i1<-1; i2<-1
j1<-2; j2<-3;
ret <-matrix(1,4,4)[i1:i2,j1:j2] ;
 
dim(ret) is NULL because the submatrix single col or single row is coerce to a vector automaticaly.
How can i bypass this cast  : submatrix->vector   ???????

help("[") 

drop=FALSE is what you're looking for

O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907