DZone Snippets: slice code

Rubylike slice for strings and lists

mdemare (Michiel de Mare) — Wed, 30 Jan 2008 13:26:39 GMT

(slice "hello" 2 4) => "ll"
Comparable to: "hello"[2...4]

(slice "hello" 2 -1) => "ll"
Comparable to: "hello"[2...-1]

(slice "hello" '(2 2)) => "ll"
Comparable to: "hello"[2,2]

(slice "hello" 1) => "ello"
Comparable to: "hello"[2..-1]



(def slice (str x (o y))

  (if (atom x)

    (if 

      ; (slice "hello" 1) => "ello"

      (no y) 

        (subseq str x)

      ; (slice "hello" 2 -1) => "ll"

      (< y 0) 

        (subseq str x (+ (len str) y))

      ; (slice "hello" 2 4) => "ll"

      (subseq str x y))

    ; (slice "hello" '(2 2)) => "ll"

    (subseq str (car x) (+ (car x) (cadr x)))))

Split String into roughly equal-sized chunks.

duncanbeevers (Duncan Beevers) — Thu, 21 Sep 2006 00:29:28 GMT

Split a string into an array of roughly equal sized chunks based on a string or regular expression delimiter.
Delimiter is preserved in output.



class String

  def chunk_string(average_segment_size = 40, sclice_on = /\s+/)

    out = []

    slices_estimate = self.size.divmod(average_segment_size)

    slice_count = (slices_estimate[1] > 0 ? slices_estimate[0] + 1 : slices_estimate[0])

    slice_guess = self.size / slice_count

    previous_slice_location = 0

    (1..slice_count - 1).each do

      |i|

      slice_location = self.nearest_split(slice_guess * i, sclice_on)

      out << self.slice(previous_slice_location..slice_location)

      previous_slice_location = slice_location + 1

    end

    out << self.slice(previous_slice_location..self.size)

    out

  end



  def nearest_split(slice_start, slice_on)

    left_scan_location  = (self.slice(0..slice_start).rindex(slice_on)).to_i

    right_scan_location = (self.slice((slice_start+1)..self.size).index(slice_on)).to_i + slice_start

    ((slice_start - left_scan_location) < (right_scan_location - slice_start) ? left_scan_location : right_scan_location)

  end

end

slice function

gregg.irwin (Gregg Irwin) — Tue, 10 Jan 2006 06:29:24 GMT



slice: func [series start len] [copy/part at series start len]