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--- fuss:ruby [2015/01/09 05:34]
127.0.0.1 external edit
+++ fuss:ruby [2017/02/22 18:30] (current)
@@ Line 1: / Line 1: @@
+====== Reverse List ======
+<code ruby>
+###########################################################################
+##  Copyright (C) Wizardry and Steamworks 2013 - License: GNU GPLv3      ##
+###########################################################################
+def wasListReverse(list = [])
+  if list.length <= 1; return list; end
+  return wasListReverse(list[1..-1]) + [ list[0] ]
+end
+</code>
+====== Map Preserving Sort using Quicksort for Integers ======
+<code ruby>
+###########################################################################
+##  Copyright (C) Wizardry and Steamworks 2013 - License: GNU GPLv3      ##
+###########################################################################
+def wasDualQuicksort(a = [], b = [])
+  raise("The sorted arrays must be of equal length.") unless(a.length == b.length)
+  if a.length <= 1
+    return a + b
+  end
+  pivot_a = a[0]
+  a.shift
+  pivot_b = b[0]
+  b.shift
+  less = []
+  less_b = []
+  more = []
+  more_b = []
+  while not a.empty?
+    if(a[0] > pivot_a)
+      less.unshift(a[0])
+      less_b.unshift(b[0])
+    else
+      more.unshift(a[0])
+      more_b.unshift(b[0])
+    end
+    a.shift
+    b.shift
+  end
+  return wasDualQuicksort(less, less_b) + [ pivot_a ] + [ pivot_b ] + wasDualQuicksort(more, more_b)
+end
+</code>
+====== List Stride ======
+Returns a strided list starting from the element index ''start'' with a stride of ''stride''. In other words, returns every ''stride''-element starting from the index ''start''.
+For example, given a list:
+<code ruby>
+a = [30, "g", 20, "c", 10, "a", 9, "f", 8, "d", 7, "e", 5, "b"]
+</code>
+the call:
+<code ruby>
+wasListStride(a, 0, 2)
+</code>
+will return the list:
+<code ruby>
+[ 30, 20, 10, 9, 8, 7, 5 ]
+</code>
+Given the same list, a call:
+<code ruby>
+wasListStride(a, 1, 2)
+</code>
+will return the list:
+<code ruby>
+[ "g", "c", "a", "f", "d", "e", "b" ]
+</code>
+<code ruby>
+###########################################################################
+##  Copyright (C) Wizardry and Steamworks 2013 - License: GNU GPLv3      ##
+###########################################################################
+def wasListStride(list=[], start=0, stride=0)
+  if start > 0
+    list.shift
+    return wasListStride(list, start-=1, stride)
+  end
+  return [ list[0] ] + stride.step(list.size-1, stride).map { |i| list[i] }
+end
+</code>
+====== Get Symlink Path ======
+<code ruby>
+require 'pathname'
+Pathname.new('/path/to/symlink').realpath
+</code>
+====== Sort Files Into Directories ======
+The following program is meant to run in a directory containing unsorted files. The script creates directories ''0'' to ''9'' and ''A'' to ''Z'' and puts the files inside those directories by the first character of the file name.
+<code ruby>
+#!/usr/bin/ruby
+###########################################################################
+##  Copyright (C) Wizardry and Steamworks 2015 - License: GNU GPLv3      ##
+###########################################################################
+# Get all the files in the current directory.
+entries = Dir.entries(
+    Dir.pwd
+).select(
+    &lambda{
+        |x|
+        !File.directory?("#{x}") &&
+            File.basename("#{$0}").casecmp(x) != 0 # omit us!
+    }
+)
+# Sort files in [0-9A-Z] directories.
+("0".."9").to_a.concat(('A'..'Z').to_a).each do |dir|
+    begin
+        if !Dir.exists?(dir)
+            Dir.mkdir(dir)
+        end
+        entries.select(&lambda{|x| "#{x}".chars.first.casecmp(dir) == 0}).each do |file|
+            File.rename(file, File.join(dir, file))
+        end
+    rescue
+        puts "Could not move files to: " + dir
+    end
+end
+</code>
+An example application is a directory containing a bunch of archives which you want to sort into directories from ''0'' to ''9'' and ''A'' to ''Z''.