Sort Strings with Embedded Numbers Based on Their Numeric Order
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".
SortMixed(x, decreasing=FALSE, na.last=TRUE, blank.last=FALSE,
numeric.type=c("decimal", "roman"),
roman.case=c("upper","lower","both") )
OrderMixed(x, decreasing=FALSE, na.last=TRUE, blank.last=FALSE,
numeric.type=c("decimal", "roman"),
roman.case=c("upper","lower","both") )x |
vector to be sorted. |
decreasing |
logical. Should the sort be increasing or
decreasing? Note that |
na.last |
logical, controlling the treatment of |
blank.last |
logical, controlling the treatment of blank values. If |
numeric.type |
either |
roman.case |
one of |
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.
OrderMixed returns a vector giving the sort order of the input
elements. SortMixed returns the sorted vector.
Gregory R. Warnes greg@warnes.net
## 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 SortMixed does the 'right' thing
SortMixed(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"))
OrderMixed(x)
SortMixed(x) # Notice that plain numbers, including 'Inf' show up
# before strings, NAs at the end, and blanks at the
# beginning .
SortMixed(x, na.last=TRUE) # default
SortMixed(x, na.last=FALSE) # push NAs to the front
SortMixed(x, blank.last=FALSE) # default
SortMixed(x, blank.last=TRUE) # push blanks to the end
SortMixed(x, decreasing=FALSE) # default
SortMixed(x, decreasing=TRUE) # reverse sort order
## Roman numerals
chapters <- c("V. Non Sequiturs", "II. More Nonsense",
"I. Nonsense", "IV. Nonesensical Citations",
"III. Utter Nonsense")
SortMixed(chapters, numeric.type="roman" )
## Lower-case Roman numerals
vals <- c("xix", "xii", "mcv", "iii", "iv", "dcclxxii", "cdxcii",
"dcxcviii", "dcvi", "cci")
(ordered <- SortMixed(vals, numeric.type="roman", roman.case="lower"))
RomanToInt(ordered)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.