[R] sort a data.frame

[jim holtman]

> dd
      b x y z
1  chr2 A 8 1
2  chr1 D 3 1
3 chr15 A 9 1
4 chr13 C 9 2
> # add column with just numbers
> dd$sort <- as.integer(gsub("\\D+", "", dd$b))
> dd[order(dd$sort),]  # notice it is a numeric, not character order
      b x y z sort
2  chr1 D 3 1    1
1  chr2 A 8 1    2
4 chr13 C 9 2   13
3 chr15 A 9 1   15
>


On Thu, May 20, 2010 at 8:28 AM, Yuan Jian <jayuan2008 at yahoo.com> wrote:
> Hello,
>
> I have a dataframe:
> dd <- data.frame(b = c("chr2", "chr1", "chr15", "chr13"),
>       x = c("A", "D", "A", "C"), y = c(8, 3, 9, 9),
>        z = c(1, 1, 1, 2))
>
>>dd
>       b x y z
> 1  chr2 A 8 1
> 2  chr1 D 3 1
> 3 chr15 A 9 1
> 4 chr13 C 9 2
>
> Now I want to sort them according column "b", but only its number is considered:
>       b x y z
> 1  chr1 D 3 1
> 2 chr13 C 9 2
> 3 chr15 A 9 1
> 4  chr2 A 8 1
>
> thanks
> jian
>
>
>
>
>
>
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>
>
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-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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