use for loop to call multiple functions in lua

Question

I want to call multiple methods in lua that are very similar except their parameters change by one character. The way I'm doing it now works but is extremely in efficient.

function scene:createScene(event)

screenGroup = self.view

level1= display.newRoundedRect( 50, 110, 50, 50, 5 )
level1:setFillColor( 100,0,200 )
level2= display.newRoundedRect( 105, 110, 50, 50, 5 )
level2:setFillColor (100,200,0)
--and so on so forth

screenGroup:insert (level1)
screenGroup:insert (level2)
screenGroup:insert (level3)
screenGroup:insert (level4)

end

I plan on extending the screenGroop:insert method to hundreds of levels, maybe up to (level300). As you can see the way I'm doing it now is inefficient. I tried doing

for i=1, 4, 1 do 
screenGroup:insert(level..i)
end

but I get the error "table expected."

possible duplicate of Create multiple variables using for loop in lua — Etan Reisner
– Etan Reisner, Commented Nov 26, 2014 at 18:54

Community · Accepted Answer · 2017-05-23 12:17:45Z

3

The best way in this case is to probably use a table:

local levels = {}
levels[1] = display.newRoundedRect( 50, 110, 50, 50, 5 )
levels[1]:setFillColor( 100,0,200 )
levels[2] = display.newRoundedRect( 105, 110, 50, 50, 5 )
levels[2]:setFillColor (100,200,0)
--and so on so forth

for _, level in ipairs(levels) do
  screenGroup:insert(level)
end

For other alternatives check the SO answer from @EtanReisner's comment.

edited May 23, 2017 at 12:17

CommunityBot

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answered Nov 26, 2014 at 19:16

Paul Kulchenko

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Comments

David · Accepted Answer · 2014-11-27 18:55:23Z

-1

If your 'level' tables are global, which is appears they are, you can use getfenv to index them.

for i = 1, number_of_levels do
    screenGroup:insert(getfenv()["level" .. i])
end

getfenv returns the environment, with all global variables, in the form of a dictionary. Therefore, you can index it like a normal table like getfenv()["key"]

answered Nov 27, 2014 at 18:55

David

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