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series-slice.r

REBOL [ Title: "Series Slice" Date: 4-Aug-2004 Version: 1.0.1 File: %series-slice.r Author: "Stan Silver" Email: %stasil213--yahoo--com Purpose: {Provides array slicing for series} Notes: { To define the function: do %series-slice.r To run the tests: do/args %series-slice.r 'test } Example: { ;; ====================== ;; slice series to ;; slice series [from] ;; slice series [from to] ;; ====================== str: "hello world" slice str 2 >> "he" slice str -3 >> "hello wor" slice str [2] >> "ello world" slice str [-3] >> "rld" slice str [2 5] >> "ello" slice str [3 -2] >> "llo worl" slice str [-4 -2] >> "orl" slice str [-2 2] >> "" } History: { 1.0.1 code clean-up (with help from Anton) 1.0.0 initial version } Library: [ level: 'beginner platform: 'all type: 'function domain: 'extension tested-under: none support: none license: none see-also: none ] ] slice: function [series [series!] from-to [block! integer!]][ ;; ====================== ;; slice series to ;; slice series [from] ;; slice series [from to] ;; ====================== start end distance ][ either block? from-to [ start: from-to/1 end: either (length? from-to) = 1 [length? series] [from-to/2] ][ start: 1 end: from-to ] if start < 0 [start: (length? series) + 1 + start] if end < 0 [end: (length? series) + 1 + end] distance: end - start + 1 either distance > 0 [ copy/part (at series start) distance ][ clear copy series ] ] if 'test = system/script/args [context [ ;; ============================= ;; test function ;; ;; to run tests: ;; do/args %series-slice.r 'test ;; ============================= tests: 0 succeeded: 0 ?: func [result 'ignore desired] [ tests: tests + 1 either result = desired [ succeeded: succeeded + 1 ][ print ["TEST FAILED" mold result ignore mold desired] ] ] ;; ===== ;; tests ;; ===== a: [2 3 4 5 6 7 8] ? slice a 2 >> [2 3] ? slice a -3 >> [2 3 4 5 6] ? slice a [2] >> [3 4 5 6 7 8] ? slice a [-3] >> [6 7 8] ? slice a [2 5] >> [3 4 5 6] ? slice a [3 -2] >> [4 5 6 7] ? slice a [-4 -2] >> [5 6 7] ? slice a [-2 2] >> [] b: "hello world" ? slice b 2 >> "he" ? slice b -3 >> "hello wor" ? slice b [2] >> "ello world" ? slice b [-3] >> "rld" ? slice b [2 5] >> "ello" ? slice b [3 -2] >> "llo worl" ? slice b [-4 -2] >> "orl" ? slice b [-2 2] >> "" print ["Tests:" tests "Succeeded:" succeeded] ]]
halt ;; to terminate script if DO'ne from webpage
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