How to order a character vector in ascend form in R

Question

Hi everybody I am trying to solve a problem in R. I want to read a lot of files allocated in multiples sub folders in a main folder. Then I used list.files() t

Answer 1

gtools::mixedsort is designed for this...

gtools::mixedsort( c("A1","A10","A11","A12","A13","A14","A15","A2","A3","A4","A5","A6","A7") )
[1] "A1"  "A2"  "A3"  "A4"  "A5"  "A6"  "A7"  "A10" "A11" "A12" "A13" "A14" "A15"

Thanks to @Matthew for the data

Answer 2

Rather than focussing on a particular example I suggest using an existing tool, mixedsort in the gtools package that handles irregular widths of both the alpha and numeric characters.

require(gtools)
vec <- paste0( replicate(40, {
            paste( sample(LETTERS, 3, repl=TRUE),collapse="")}),  
                sample(1:400, 40, repl=TRUE) ) 
mixedsort(vec)
 [1] "ABP256" "ATV361" "ATZ12"  "BKL273" "BOY273" "BQJ242" "CQL129"
 [8] "CXH313" "CXQ249" "DFU116" "FGI305" "HJK249" "ICN4"   "IML75" 
[15] "JDJ309" "JEB93"  "JHF276" "JIY265" "JXK287" "KCQ282" "MAR161"
[22] "MGV185" "MHH72"  "NDJ84"  "NGZ84"  "OIV207" "ORK31"  "PSJ95" 
[29] "QOC178" "QXL344" "QYK285" "RFO98"  "ROC135" "TUL40"  "UBT134"
[36] "UKP14"  "VQL372" "YLG393" "ZLD394" "ZSG180"

If mixedsort didn't exist man would need to invent it. This is not exactly going to produce the same results but it might light a path forward:

vec[ order( gsub("[[:digit:]]", "", vec), gsub("[[:alpha:]]", "", vec) )]
 [1] "ABP256" "ATV361" "ATZ12"  "BKL273" "BOY273" "BQJ242" "CQL129"
 [8] "CXH313" "CXQ249" "DFU116" "FGI305" "HJK249" "ICN4"   "IML75" 
[15] "JDJ309" "JEB93"  "JHF276" "JIY265" "JXK287" "KCQ282" "MAR161"
[22] "MGV185" "MHH72"  "NDJ84"  "NGZ84"  "OIV207" "ORK31"  "PSJ95" 
[29] "QOC178" "QXL344" "QYK285" "RFO98"  "ROC135" "TUL40"  "UBT134"
[36] "UKP14"  "VQL372" "YLG393" "ZLD394" "ZSG180"

It collapse all the alpha characters together before the numerics and would order "a12b" before "a99z".

Answer 3

There are a few ways to do this. Here's another one:

b <- c("A1","A10","A11","A12","A13","A14","A15","A2","A3","A4","A5","A6","A7")
b[order(nchar(b), b)]
# [1] "A1"  "A2"  "A3"  "A4"  "A5"  "A6"  "A7"  "A10" "A11" "A12" "A13" "A14" "A15"

Answer 4

If this is the exact data that you have, you can sort it the way you want like this:

> b[order(as.integer(substr(b,2,3)))]
 [1] "A1"  "A2"  "A3"  "A4"  "A5"  "A6"  "A7"  "A8"  "A9"  "A10" "A11" "A12"
[13] "A13" "A14" "A15"

If the actual data is more complicated, you might have to do a little more string manipulation, but this is the general idea.