R: Order or Sort strings with embedded numbers so that the...

mixedsort {gtools} | R Documentation

## Order or Sort strings with embedded numbers so that the numbers are in the correct order

### Description

These functions sort or order character strings containing embedded numbers so that the numbers are numerically sorted rather than sorted by character value. I.e. "Asprin 50mg" will come before "Asprin 100mg". In addition, case of character strings is ignored so that "a", will come before "B" and "C".

### Usage

    mixedsort(x, decreasing=FALSE, na.last=TRUE, blank.last=FALSE,
              numeric.type=c("decimal", "roman"),
              roman.case=c("upper","lower","both") )
    mixedorder(x, decreasing=FALSE, na.last=TRUE, blank.last=FALSE,
              numeric.type=c("decimal", "roman"),
              roman.case=c("upper","lower","both") )

### Arguments

`x` | Vector to be sorted.
`decreasing` | logical. Should the sort be increasing or decreasing? Note that `descending=TRUE` reverses the meanings of `na.last` and `blanks.last`.
`na.last` | for controlling the treatment of `NA` values. If `TRUE`, missing values in the data are put last; if `FALSE`, they are put first; if `NA`, they are removed.
`blank.last` | for controlling the treatment of blank values. If `TRUE`, blank values in the data are put last; if `FALSE`, they are put first; if `NA`, they are removed.
`numeric.type` | either "decimal" (default) or "roman". Are numeric values represented as decimal numbers (`numeric.type="decimal"`) or as Roman numerals (`numeric.type="roman"`)?
`roman.case` | one of "upper", "lower", or "both". Are roman numerals represented using only capital letters ('IX') or lower-case letters ('ix') or both?

### Details

I often have character vectors (e.g. factor labels), such as compound and dose, that contain both text and numeric data. This function is useful for sorting these character vectors into a logical order.

It does so by splitting each character vector into a sequence of character and numeric sections, and then sorting along these sections, with numbers being sorted by numeric value (e.g. "50" comes before "100"), followed by characters strings sorted by character value (e.g. "A" comes before "B") ignoring case (e.g. 'A' has the same sort order as 'a').

By default, sort order is ascending, empty strings are sorted to the front, and `NA` values to the end. Setting `descending=TRUE` changes the sort order to descending and reverses the meanings of `na.last` and `blank.last`.

Parsing looks for decimal numbers unless `numeric.type="roman"`, in which parsing looks for roman numerals, with character case specified by `roman.case`.

### Value

`mixedorder` returns a vector giving the sort order of the input elements. `mixedsort` returns the sorted vector.

### Author(s)

Gregory R. Warnes greg@warnes.net

### See Also

`sort`, `order`

### Examples

    ## compound & dose labels
    Treatment <- c("Control", "Asprin 10mg/day", "Asprin 50mg/day",
                   "Asprin 100mg/day", "Acetomycin 100mg/day",
                   "Acetomycin 1000mg/day")

    ## ordinary sort puts the dosages in the wrong order
    sort(Treatment)

    ## but mixedsort does the 'right' thing
    mixedsort(Treatment)

    ## Here is a more complex example
    x <- rev(c("AA 0.50 ml", "AA 1.5 ml", "AA 500 ml", "AA 1500 ml",
               "EXP 1", "AA 1e3 ml", "A A A", "1 2 3 A", "NA", NA, "1e2",
               "", "-", "1A", "1 A", "100", "100A", "Inf"))

    mixedorder(x)

    mixedsort(x)  # Notice that plain numbers, including 'Inf' show up
                  # before strings, NAs at the end, and blanks at the
                  # beginning .

    mixedsort(x, na.last=TRUE)  # default
    mixedsort(x, na.last=FALSE) # push NAs to the front

    mixedsort(x, blank.last=FALSE) # default
    mixedsort(x, blank.last=TRUE)  # push blanks to the end

    mixedsort(x, decreasing=FALSE) # default
    mixedsort(x, decreasing=TRUE)  # reverse sort order

    ## Roman numerals
    chapters <- c("V. Non Sequiturs", "II. More Nonsense",
                  "I. Nonsense", "IV. Nonesensical Citations",
                  "III. Utter Nonsense")
    mixedsort(chapters, numeric.type="roman" )

    ## Lower-case Roman numerals
    vals <- c("xix", "xii", "mcv", "iii", "iv", "dcclxxii",   "cdxcii",
              "dcxcviii",   "dcvi",   "cci")
    (ordered <- mixedsort(vals, numeric.type="roman", roman.case="lower"))
    roman2int(ordered)

[Package gtools version 3.8.1 Index]