R help - Jun 2011 - Sorting a data frame with values of different lengths

Hi all,

I am attempting to run a script in which I permute my data and run a
Wilcoxon rank sum test on the data 1000 times and compare my original test
statistic to the permuted test statistics to more accurately estimate a
significance level for the trends I am observing.

In the process of doing this, I need to sort a data frame that measures 3 x
1001 based on the value of the test statistic (W).  I am trying to get the
data in ascending order based on W.  My data frame looks something like
this:
> W_table
   pds_gagehandles.i.  p     W
W                mibe  1   746
2                mibe  2 870.5
3                mibe  3   767
4                mibe  4  1066
5                mibe  5   885
6                mibe  6 931.5
7                mibe  7   765
8                mibe  8   930
9                mibe  9 696.5
10               mibe 10 711.5
11               mibe 11  1006

I am trying to sort it using the command: > W_table[order(W_table$W),],
which is spitting out:

   pds_gagehandles.i.  p     W
11               mibe 11  1006
4                mibe  4  1066
9                mibe  9 696.5
10               mibe 10 711.5
W                mibe  1   746
7                mibe  7   765
3                mibe  3   767
2                mibe  2 870.5
5                mibe  5   885
8                mibe  8   930
6                mibe  6 931.5

I want this data frame to have the values that are currently the first two
as the last two, i.e. I need it in ascending order.  I am thinking that I am
having this problem because W is different lengths and ?order states the
data should be "a sequence of numeric, complex, character or logical
vectors, all of the same length, or a classed R object".  Maybe because the
values over 1000 have an extra digit R is seeing them as '100' for some
reason? Does anyone know of another function I can use to accomplish this
task or a way to work around this error?

Thank you very much,

Billy

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Hi,

It looks to me that your data frame is being sorted as text.

What does
str(W_table)
show?

How was W_table created? Your W column appears to not be numeric.

Sarah

On Tue, Jun 7, 2011 at 9:51 AM, William Armstrong
<William.Armstrong at noaa.gov> wrote:
> Hi all,
>
> I am attempting to run a script in which I permute my data and run a
> Wilcoxon rank sum test on the data 1000 times and compare my original test
> statistic to the permuted test statistics to more accurately estimate a
> significance level for the trends I am observing.
>
> In the process of doing this, I need to sort a data frame that measures 3 x
> 1001 based on the value of the test statistic (W). ?I am trying to get the
> data in ascending order based on W. ?My data frame looks something like
> this:
>
>> W_table
> ? pds_gagehandles.i. ?p ? ? W
> W ? ? ? ? ? ? ? ?mibe ?1 ? 746
> 2 ? ? ? ? ? ? ? ?mibe ?2 870.5
> 3 ? ? ? ? ? ? ? ?mibe ?3 ? 767
> 4 ? ? ? ? ? ? ? ?mibe ?4 ?1066
> 5 ? ? ? ? ? ? ? ?mibe ?5 ? 885
> 6 ? ? ? ? ? ? ? ?mibe ?6 931.5
> 7 ? ? ? ? ? ? ? ?mibe ?7 ? 765
> 8 ? ? ? ? ? ? ? ?mibe ?8 ? 930
> 9 ? ? ? ? ? ? ? ?mibe ?9 696.5
> 10 ? ? ? ? ? ? ? mibe 10 711.5
> 11 ? ? ? ? ? ? ? mibe 11 ?1006
>
> I am trying to sort it using the command: > W_table[order(W_table$W),],
> which is spitting out:
>
> ? pds_gagehandles.i. ?p ? ? W
> 11 ? ? ? ? ? ? ? mibe 11 ?1006
> 4 ? ? ? ? ? ? ? ?mibe ?4 ?1066
> 9 ? ? ? ? ? ? ? ?mibe ?9 696.5
> 10 ? ? ? ? ? ? ? mibe 10 711.5
> W ? ? ? ? ? ? ? ?mibe ?1 ? 746
> 7 ? ? ? ? ? ? ? ?mibe ?7 ? 765
> 3 ? ? ? ? ? ? ? ?mibe ?3 ? 767
> 2 ? ? ? ? ? ? ? ?mibe ?2 870.5
> 5 ? ? ? ? ? ? ? ?mibe ?5 ? 885
> 8 ? ? ? ? ? ? ? ?mibe ?8 ? 930
> 6 ? ? ? ? ? ? ? ?mibe ?6 931.5
>
> I want this data frame to have the values that are currently the first two
> as the last two, i.e. I need it in ascending order. ?I am thinking that I
am
> having this problem because W is different lengths and ?order states the
> data should be "a sequence of numeric, complex, character or logical
> vectors, all of the same length, or a classed R object". ?Maybe
because the
> values over 1000 have an extra digit R is seeing them as '100' for
some
> reason? Does anyone know of another function I can use to accomplish this
> task or a way to work around this error?
>
> Thank you very much,
>
> Billy
>
> --

-- 
Sarah Goslee
http://www.functionaldiversity.org