Lua arrays question

Question

I'm a PHP guy so I don't know how to solve this problem. I know how I'd do this in PHP but I have no clue what the constraints are for Lua regarding this problem.

T = {
  clocktable = {},
  beancabinet = {},
  --...etc
}

T.clocktable[674] = 1
T.clocktable[660] = 1
--...etc

Q: How would I loop through "T" to quickly know that the clocktable key includes the extended keys "674" and "660", only knowing "clocktable"?

Note: please be careful of overhead as the "T" table will be very loaded with data and this is in a performance environment.

Stuart P. Bentley · Accepted Answer · 2011-06-01 22:28:12Z

6

I'm not sure what the question exactly is. If you know the key, ponzao's answer is right, otherwise use a for loop:

for key, value in pairs(T.clocktable) do
    -- do something with key and value
end

edited Jun 1, 2011 at 22:28

Stuart P. Bentley

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answered Jun 1, 2011 at 20:04

Jasmijn

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4 Comments

Geekster Over a year ago

We wouldn't know the key (674, for example) of T.clocktable. Also, we will need to do actions on each key.

BMitch Over a year ago

@Geekster: The for k,v in pairs(T) syntax that Robin provided is how you loop through a table, you don't need to know 674 in advance.

kikito Over a year ago

Don't you mean T.clocktable[674] (without the second dot?)

Jasmijn Over a year ago

@egarcia: I did, an unfortunate typo. Luckily Stuart P. Bentley fixed it for me.

ponzao · Accepted Answer · 2011-06-01 20:02:38Z

1

Is there a reason not to just check if it is not nil?

T.clocktable[674] ~= nil

answered Jun 1, 2011 at 20:02

ponzao

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1 Comment

Geekster Over a year ago

We don't know "clocktable[674]" we know "clocktable" at the time of inquiry. The idea is to compile a list of keys so we can use the keys to perform actions.

Alex Lockwood · Accepted Answer · 2012-04-07 11:43:12Z

0

Try

for i, v in pairs(T.clocktable) do
    print("Key:", i, "Value:", v)
end

> Key: 674 Value: 1
> Key: 660 Value: 1

edited Apr 7, 2012 at 11:43

Alex Lockwood

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answered Jun 3, 2011 at 15:33

Matt

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