Global Functions⚓︎

Global functions in lua are the built-in funcions which are pre declared and are very useful. There are many of them but in this guide we will discuss some common global functions.

tonumber()⚓︎

tonumber(value,base) It converts the given argument in to a number of desired base (between 2-36). If second argument is missing then by default it converts the given argument into a number of base 10. In case of failure will return nil.

print(tonumber("123"))
print(tonumber("911"))
print(tonumber("abc"))

123
911
nil

tostring()⚓︎

tostring(value) It converts the given argument in to a string. Just like tonumber(), If it cannot convert it will return nil.

print("The statement was ".. tostring(true))
print("Square of 16 is : ".. tostring(16^2))

The statement was true
Square of 16 is : 256

print()⚓︎

print(value) It takes multiple arguments and display them in the console/output. In most cases it is used for debugging.

print("Eden is smart")
print("Helpers are the best")

 Eden is smart
 Helpers are the best

assert()⚓︎

assert(statement,error message) It stops the thread and returns the error message if the given statement is false or nil.

local eden =  "Brilliant"
assert(eden == "noob", "eden is not noob")

 eden is not noob

error()⚓︎

error(message) It stops the curent thread and gives the error in the output/console.

error("Program terminated!")

 Program terminated!

type()⚓︎

type(value) It returns the data type of the given argument.

local hi = true
local data = {"EdenRose","Teddy","Cake","Selfish"}
print(type(hi))
print(type(data))

 boolean
 table

pcall()⚓︎

pcall(function,...) It calls the given function in protected mode. In case of any error the thread will not be terminated. The first returned value is a bool which is either true or false depends if the call succeeded or not. If the call succeed then first value will be true and second value will be the value returned by the function called in the protected mode. If the call could not succeed then pcall will return false with the error message.

local function test(name)
    print(name)
    assert(name == "EdenRose", "Incorrect Name!")
end
local status , result = pcall(test,"Willie")
print(status,result)

 false   Incorrect Name!

unpack()⚓︎

unpack(table,initial_index,final_index) It returns elements of a table in the form of tuple, according to the given arguments. By default: initial_index = 1 final_index = #table

local tbl = {"EdenRose","Teddy","Cake","Selfish","Smart","Intelligent"}
print(unpack(tbl,2,5))

Teddy Cake Selfish Smart

select()⚓︎

select(n,args) If n is positive, It returns all the given arguments after the index n If n is negative, It returns all the given n number of arguments from the end if n is # operator, It returns the number of given arguments

print(select("#","hi","good","ok","wow","yep"))

  5

rawequal()⚓︎

rawequal(value1,value2) It returns a bool value. If given arguments are equal, it returns true. If the arguments are not equal, it returns false

print(rawequal(2,2))

 true

Thanks For Reading :)⚓︎

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