R help - Jun 2007 - How to make a table of a desired dimension

Hi ComRades,

I want to make a matrix of frequencies from vectors of a continuous 
variable spanning different values. For example this code
x<-c(runif(100,10,40),runif(100,43,55))
y<-c(runif(100,7,35),runif(100,37,50))
z<-c(runif(100,10,42),runif(100,45,52))
a<-table(ceiling(x))
b<-table(ceiling(y))
c<-table(ceiling(z))
a
b
c

will give me three tables that start and end at different integer 
values, and besides, they have 'holes' in between different integer 
values. Is it possible to use 'table' to make these three tables have 
the same dimensions, filling in the absent labels with zeroes? In the 
example above, the desired tables should all start at 8 and tables 'a' 
and 'c' should put a zero at labels '8' to '10', should
all put zeros in
the frequencies of the labels corresponding to the holes, and should all 
end at label '55'. The final purpose is the make a matrix and use 
'matplot' to plot all the frequencies in one plot, such as

#code valid only when 'a', 'b', and 'c' have the proper
dimension
p<-mat.or.vec(48,4)
p[,1]<-8:55
p[,2]<-c(matrix(a)[1:48])
p[,3]<-c(matrix(b)[1:48])
p[,4]<-c(matrix(c)[1:48])
matplot(p)

I read the help about 'table' but I couldn't figure out if dnn, 
deparse.level, or the other arguments could serve my purpose. Thanks for 
your help
Rub?n

You need to basically use table on factors with fixed pre-specified 
levels. For example:

  x <- c(runif(100,10,40), runif(100,43,55))
  y <- c(runif(100,7,35),  runif(100,37,50))
  z <- c(runif(100,10,42), runif(100,45,52))
  xx <- ceiling(x);  yy <- ceiling(y);  zz <- ceiling(z)


  mylevels <- min( c(xx, yy, zz) ) : max( c(xx, yy, zz) )

  out <- cbind( table( factor(xx, levels=mylevels) ),
                table( factor(yy, levels=mylevels) ),
                table( factor(zz, levels=mylevels) ) )

You could replace the last command with simply

  sapply( list(xx, yy, zz),
                function(vec) table( factor(vec, levels=mylevels) ) )

Regards, Adai



Rub?n Roa-Ureta wrote:
> Hi ComRades,
> 
> I want to make a matrix of frequencies from vectors of a continuous 
> variable spanning different values. For example this code
> x<-c(runif(100,10,40),runif(100,43,55))
> y<-c(runif(100,7,35),runif(100,37,50))
> z<-c(runif(100,10,42),runif(100,45,52))
> a<-table(ceiling(x))
> b<-table(ceiling(y))
> c<-table(ceiling(z))
> a
> b
> c
> 
> will give me three tables that start and end at different integer 
> values, and besides, they have 'holes' in between different integer
> values. Is it possible to use 'table' to make these three tables
have
> the same dimensions, filling in the absent labels with zeroes? In the 
> example above, the desired tables should all start at 8 and tables
'a'
> and 'c' should put a zero at labels '8' to '10',
should all put zeros in
> the frequencies of the labels corresponding to the holes, and should all 
> end at label '55'. The final purpose is the make a matrix and use 
> 'matplot' to plot all the frequencies in one plot, such as
> 
> #code valid only when 'a', 'b', and 'c' have the
proper dimension
> p<-mat.or.vec(48,4)
> p[,1]<-8:55
> p[,2]<-c(matrix(a)[1:48])
> p[,3]<-c(matrix(b)[1:48])
> p[,4]<-c(matrix(c)[1:48])
> matplot(p)
> 
> I read the help about 'table' but I couldn't figure out if dnn,
> deparse.level, or the other arguments could serve my purpose. Thanks for 
> your help
> Rub?n
> 
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