# [R] median between matrix column

arun smartpink111 at yahoo.com
Mon Oct 15 18:06:26 CEST 2012

```Dear Eliza,

No problem.

In my solution, you can delete the sort() and get the same result.
res1<-do.call(rbind,lapply(1:ncol(mat1[,-16]),function(i) median(stack(as.data.frame(mat1[,c(i,16)]))[,1])))
#     [,1]
#[1,] 239.0
#[2,] 238.0
#[3,] 181.5
#[4,] 244.5
#[5,] 265.0
#[6,] 212.0
A.K.

________________________________
From: eliza botto <eliza_botto at hotmail.com>
To: "smartpink111 at yahoo.com" <smartpink111 at yahoo.com>
Cc: "r-help at r-project.org" <r-help at r-project.org>
Sent: Monday, October 15, 2012 9:32 AM
Subject: RE: [R] median between matrix column

Dear Arun and Jessica,
regards
eliza

> Date: Mon, 15 Oct 2012 05:55:55 -0700
> From: smartpink111 at yahoo.com
> Subject: Re: [R] median between matrix column
> To: eliza_botto at hotmail.com
> CC: r-help at r-project.org
>
> HI,
> May be this helps you (if I understand it correctly):
> set.seed(1)
> mat1<-matrix(sample(1:500,160,replace=TRUE),ncol=16)
>  res<-do.call(rbind,lapply(1:ncol(mat1[,-16]),function(i) median(sort(stack(as.data.frame(mat1[,c(i,16)]))[,1]))))
>  res
> #       [,1]
>  #[1,] 239.0
>  #[2,] 238.0
>  #[3,] 181.5
>  #[4,] 244.5
>  #[5,] 265.0
>  #[6,] 212.0
>  #[7,] 228.5
>  #[8,] 233.0
>  #[9,] 182.5
> #[10,] 239.5
> #[11,] 233.5
> #[12,] 220.0
> #[13,] 235.0
> #[14,] 259.0
> #[15,] 227.0
>
> A.K.
>
>
>
>
>
> ----- Original Message -----
> From: eliza botto <eliza_botto at hotmail.com>
> To: "r-help at r-project.org" <r-help at r-project.org>
> Cc:
> Sent: Monday, October 15, 2012 8:20 AM
> Subject: [R] median between matrix column
>
>
> Dear useRs,
>
> 1.    how to calculate single median value for two columns of a matrix?
> 2.    i have a matrix of 16 columns and 365 rows, how to calculate median between columns 1 and 16, 2 and 16, 3 and 16, 4 and 16, 5 and 16 till 15th column. is there a loop command to do the said operation?
>
> regards
> eliza
>     [[alternative HTML version deleted]]
>
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