Guest User

Untitled

a guest
Nov 1st, 2018
218
Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
Lua 3.63 KB | None
  1. function test_tableremove(mylist)
  2.     for i=#mylist,1,-1 do
  3.         if mylist[i] == 13 then
  4.             table.remove(mylist, i)
  5.         end
  6.     end
  7. end -- func
  8.  
  9. function test_mitch(mylist)
  10.     -- NOTE: This is a messy, hardcoded version of my algorithm, for test-purposes.
  11.     -- Go to https://stackoverflow.com/a/53038524/8874388 for the actual, clean version.
  12.     local j, n = 1, #mylist;
  13.  
  14.     for i=1,n do
  15.         local value = mylist[i]
  16.         if value ~= 13 then -- Keep everything except "13"
  17.             -- Move i's kept value to j's position, if it's not already there.
  18.             if (i ~= j) then
  19.                 mylist[j] = mylist[i];
  20.                 mylist[i] = nil;
  21.             end
  22.             j = j + 1; -- Increment position of where we'll place the next kept value.
  23.         else -- Delete "13"
  24.             mylist[i] = nil;
  25.         end
  26.     end
  27. end
  28.  
  29. function build_tables(howMany)
  30.     local ofs = {}
  31.     for i=1,howMany do
  32.         ofs[i*50] = true;
  33.     end
  34.  
  35.     local tables = {}
  36.     for i=1, 1 do
  37.       tables[i] = {}
  38.       for j=1, 2000000 do -- 2 million items
  39.         tables[i][j] = (ofs[j] and 13 or 100) -- put a "13" (deleted) in the slots to be deleted, otherwise "100" (kept)
  40.       end
  41.     end
  42.  
  43.     return tables
  44. end
  45.  
  46. function time_func(func, name, howMany)
  47.     local tables = build_tables(howMany)
  48.     time0 = os.clock()
  49.     for i=1, #tables do
  50.         func(tables[i])
  51.     end
  52.     time1 = os.clock()
  53.     print(string.format("[%13s] elapsed time (deleting %.0f items): %.3f\n", name, howMany, time1 - time0))
  54. end
  55.  
  56. -- The number below (i) controls how many items that will need to be deleted from the array.
  57. -- This test checks if table.remove() is ever faster if you only need to remove a few entries.
  58. -- The test arrays contain 2 million items, and the items that need to be removed at all at the start,
  59. -- hence triggering the need to re-index the subsequent array entries.
  60. for i=1,6 do
  61.     time_func(test_mitch, "mitch", i)
  62.     time_func(test_tableremove, "table.remove", i)
  63. end
  64.  
  65.  
  66. --[[
  67.  
  68. LuaJIT 2.0.5 -- Copyright (C) 2005-2017 Mike Pall. http://luajit.org/
  69. JIT: ON CMOV SSE2 SSE3 SSE4.1 fold cse dce fwd dse narrow loop abc sink fuse
  70.  
  71. [        mitch] elapsed time (deleting 1 items): 0.008
  72.  
  73. [ table.remove] elapsed time (deleting 1 items): 0.010
  74.  
  75. [        mitch] elapsed time (deleting 2 items): 0.008
  76.  
  77. [ table.remove] elapsed time (deleting 2 items): 0.019
  78.  
  79. [        mitch] elapsed time (deleting 3 items): 0.008
  80.  
  81. [ table.remove] elapsed time (deleting 3 items): 0.022
  82.  
  83. [        mitch] elapsed time (deleting 4 items): 0.008
  84.  
  85. [ table.remove] elapsed time (deleting 4 items): 0.028
  86.  
  87. [        mitch] elapsed time (deleting 5 items): 0.008
  88.  
  89. [ table.remove] elapsed time (deleting 5 items): 0.031
  90.  
  91. [        mitch] elapsed time (deleting 6 items): 0.008
  92.  
  93. [ table.remove] elapsed time (deleting 6 items): 0.039
  94.  
  95.  
  96.  
  97. Lua 5.3.4  Copyright (C) 1994-2017 Lua.org, PUC-Rio
  98.  
  99. + $ lua test.lua
  100. [        mitch] elapsed time (deleting 1 items): 0.306
  101.  
  102. [ table.remove] elapsed time (deleting 1 items): 0.121
  103.  
  104. [        mitch] elapsed time (deleting 2 items): 0.309
  105.  
  106. [ table.remove] elapsed time (deleting 2 items): 0.164
  107.  
  108. [        mitch] elapsed time (deleting 3 items): 0.313
  109.  
  110. [ table.remove] elapsed time (deleting 3 items): 0.237
  111.  
  112. [        mitch] elapsed time (deleting 4 items): 0.326
  113.  
  114. [ table.remove] elapsed time (deleting 4 items): 0.262
  115.  
  116. [        mitch] elapsed time (deleting 5 items): 0.326
  117.  
  118. [ table.remove] elapsed time (deleting 5 items): 0.304
  119.  
  120. [        mitch] elapsed time (deleting 6 items): 0.334
  121.  
  122. [ table.remove] elapsed time (deleting 6 items): 0.341
  123.  
  124.  
  125.  
  126. ]]--
RAW Paste Data Copied