[R] Custom Sort Character and Numeric

[jim holtman]

Here is another solution that gets the order you posted:

> myArray <- c('AFP9','AFR9','TLQP7','AFS9','AFR8','AFP8','AFS7','TLQS8')
> # create a sort key
> key <- sub("^(.*)(.)(.)$", "\\3\\2\\1", myArray)
> key
[1] "9PAF"  "9RAF"  "7PTLQ" "9SAF"  "8RAF"  "8PAF"  "7SAF"  "8STLQ"
> # sort, but don't get your output
> myArray[order(key)]
[1] "TLQP7" "AFS7"  "AFP8"  "AFR8"  "TLQS8" "AFP9"  "AFR9"  "AFS9"
> # to get your output, new key
> newKey <- sub("^(.*)(.)(.)$", "\\1\\3\\2", myArray)
> newKey
[1] "AF9P"  "AF9R"  "TLQ7P" "AF9S"  "AF8R"  "AF8P"  "AF7S"  "TLQ8S"
> myArray[order(newKey)]
[1] "AFS7"  "AFP8"  "AFR8"  "AFP9"  "AFR9"  "AFS9"  "TLQP7" "TLQS8"
>


On Sun, Oct 16, 2011 at 4:47 AM, swonder03 <ramey.steven at gmail.com> wrote:
> I"m trying to do a custom sort in this order:
>
> 1) Numeric digit furthest right;
> 2) Alphabetical second furthest to the right;
> 3) Alphabetical the rest of the string beginning with the first character;
>
> The example code I'm using is an array that follows:
>
> /myArray <- c('AFP9','AFR9','TLQP7','AFS9','AFR8','AFP8','AFS7','TLQS8')/
>
> The output I desire is:
>
> />myArray
> [1] "AFS7" "AFP8" "AFR8"  "AFP9" "AFR9" "AFS9" "TLQP7" TLQS8"  /
>
> What I'm thinking is writing a function that will order it by analyzing it
> from right to left. Ideally there would be a way to look at the individual
> strings like the formula in Excel "=RIGHT(cell, 1)" and drop the furthest
> right then do the same thing to the next character. I've been looking into
> custom sort for R and haven't found much. Any idea what this function would
> look like? Possibly a while loop? Each string would have a length of at
> least 3, possibly longer. Thank you in advance.
>
>
>
> --
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-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?