naturally

Go implementation of a natural sort. Numbers and non-numbers are treated as separate sub-parts to make the sort more natural for human readability. Inspired by the Perl implementation Sort::Naturally.

Install

go get github.com/dangogh/naturally

Usage

files := []string{"photo10.jpg", "photo9.jpg", "photo1.jpg"}

naturally.Sort(files)
// [photo1.jpg photo9.jpg photo10.jpg]
// a plain sort.Strings would give [photo1.jpg photo10.jpg photo9.jpg]

naturally.SortCI(files) // same, ignoring case

For use with sort.Sort / sort.Stable directly, the StringSlice and CIStringSlice types implement sort.Interface:

sort.Stable(naturally.StringSlice(files))
sort.Stable(naturally.CIStringSlice(files))

Ordering rules

• Numeric segments compare by value, with no digit limit, so "99999999999999999999" sorts before "100000000000000000000".
• Equal values with different widths order by the shorter run first: "A1" < "A01" < "A001".
• A string containing a digit sorts before one that does not, so "b2" < "Banana". The alphabetic prefixes are not compared when only one side has digits.
• Segments of non-ASCII digits (for example Arabic-Indic ٣) are compared as text rather than by value.
• SortCI uses simple Unicode case folding. Values that differ only by case compare equal, so use sort.Stable if you need their relative order preserved.