What are keys in arrays or dictionaries in Lua?

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#1

I think I know what keys in Lua but I am not sure if it is correct.

#2

Keys are just “indexes” for dictionaries.

local dictionary = {
   key = value
}

--key would be something like an index for a dictionary

Not sure how to properly explain this.

You can access them by doing:

Dictionary[keyName] --returns the value for that key
#3

So If I loop through a dictionary “i” is the key and “v” is the value?

#4

Keys are how you reference data in a table. In an array, the key is just what place that value is in the table.

local names = {"John", "Lucy", "Kevin", "Bob"}
--Keys are 1,2,3,4
print(names[2]) --> Lucy

In a dictionary, the keys are the first value.

local levels = {
["John"] = 5,
["Lucy"] = 10,
["Kevin"] = 2,
["Bob"] = 1
}
--Keys are John, Lucy, Kevin, Bob
print(levels["John"]) --> 5

That is correct.

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#5

For example if you take a book, any book you want, then for example its page numbers are keys for that book’s pages. Page number 13 - key 13 refers to some page that indeed has a number 13.

So in programming languages and specifically in Lua - tables are indexed by keys. These can be numbers or other objects such as strings, other tables or even models from your game.

A table holds values that you can only extract using a key that is assigned to them (or iterators that iterate through a table).

Example:

table_example = {
    [1] = "value1",
    ["hello"] = "value2"
}

To get “value1” you need to use key 1

table_example[1] -- gives you "value1"

To get “value2” you need to use key “hello”

table_example["hello"] -- gives you "value2"