garrysmod

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Allows you to check if thing is among values. Using the function, we can do this:

local myUsergroup = 'user'
if util.In( myUsergroup, 'user', 'vip' ) then
    -- ...
end

... instead of:

local allowedUsergroups = {
    user = true,
    vip = true,
}

local myUsergroup = 'user'
if allowedUsergroups[ myUsergroup ] then
    -- ...
end

... or:

local myUsergroup = 'user'
if myUsergroup == 'user' or myUsergroup == 'vip' then
    -- ...
end

Of course, the second code is faster because it performs a key lookup (which is O(1) vs. my O(n) implementation), but util.In is useful in contexts where performance is not so important

Bad naming aside,

local myUsergroup = 'user'
if table.HasValue( { 'user', 'vip' }, myUsergroup ) then
    -- ...
end

I understand this is less efficient than the proposed method, but by your own admission that is not the focus here.

Not creating the table would indeed be much more efficient when JIT compiles the select calls. Not as efficient as creating a hashtable with true vals, but for dynamic vararg values, this seems like the best solution. Efficiency should be the focus of this addition.

Not sure how I can improve on my solution ( except for brandonsturgeon's suggestion). Of course, pretty much the same thing can be done using table.HasValue (honestly, I just forgot this function existed), but my method is a bit faster.

Regarding the function name - I was guided by Python syntax:

if thing in (a, b, c):
    # ...

Bad naming aside,

local myUsergroup = 'user'
if table.HasValue( { 'user', 'vip' }, myUsergroup ) then
    -- ...
end

I understand this is less efficient than the proposed method, but by your own admission that is not the focus here.

Yes, performance is not a focus, because in that case I will use a key lookup. However, the developed solution, although similar to table.HasValue, is slightly more optimized. In this case, I see my function as a compromise between readability and speed - we sacrifice speed for readability, but not as much as in the case of using table.HasValue

With regards to the name, util.InValues?

util.In:
        sum = 0.286
        avg = 0.00286
        median = 0.0030000000000001
util.In2:
        sum = 0.0020000000000024
        avg = 2.0000000000024e-05
        median = 0

function util.In2( thing, ... )
  local iMax, i = select( '#', ... ), 1

  ::iter::
  if thing == select( i, ... ) then
    return true
  end
  i = i + 1
  if i <= iMax then goto iter end

    return false
end

util.In:
        sum = 0.286
        avg = 0.00286
        median = 0.0030000000000001
util.In2:
        sum = 0.0020000000000024
        avg = 2.0000000000024e-05
        median = 0

function util.In2( thing, ... )
  local iMax, i = select( '#', ... ), 1

  ::iter::
  if thing == select( i, ... ) then
    return true
  end
  i = i + 1
  if i <= iMax then goto iter end

    return false
end

Sample size and size of ...?

Sample size and size of ...?

lib: https://github.com/Be1zebub/Small-GLua-Things/blob/master/sh_benchmark.lua

util.In:
        sum = 0.035
        avg = 0.00035
        median = 0
util.In2:
        sum = 0.00099999999999767
        avg = 9.9999999999767e-06
        median = 0
        
	benchmark("util.In", function()
		a = util.In(userName, "admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user",		userName)
	end, 1000, 100)
	benchmark("util.In2", function()
		a = util.In2(userName, "admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "admin", "test", "user", "admin", "test", "user", "admin", "test", "user","admin", "test", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user", "user",  userName)
	end, 1000, 100)

table unpack

util.In:
        sum = 0.113
        avg = 0.00113
        median = 0.0010000000000048
util.In2:
        sum = 6.415
        avg = 0.06415
        median = 0.063000000000017
        
local a = false
local users = {}
local userName = "superadmin"

for i = 1, 253 do
	if i % 2 == 0 then
		users[i] = "admin"
	else
		users[i] = "user"
	end
end

users[254] = 'superadmin'

benchmark("util.In", function()
	a = util.In(userName, unpack(users))
end, 1000, 100)
benchmark("util.In2", function()
	a = util.In2(userName, unpack(users))
end, 1000, 100)