Difference between revisions of "Basic lua: Operators"

From The Official Visionaire Studio: Adventure Game Engine Wiki
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{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 1: if condition is true (method 1) !!
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! if condition is true (method 1) !!
 
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|-
 
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{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 2: if condition is true (method 2) !!
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! if condition is true (method 2) !!
 
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|-
 
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{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 3: if condition is false !!
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! if condition is false !!
 
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|-
 
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{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 4: if condition is not met, then do else !!
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! if condition is not met, then do else !!
 
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{| class="ts"
 
{| class="ts"
 
|-
 
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! Example 5: if condition is not met, then do elseif !!
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! if condition is not met, then do elseif !!
 
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|}  
 
|}  
  
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=== and ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 1: if condition a is true and condition b is false then !!
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! if condition a is true and condition b is false then !!
 
|-
 
|-
 
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|}
 
|}
  
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=== or ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 2: if condition is true or condition == true then !!
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! if condition is true or condition == true then !!
 
|-
 
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|}
 
|}
  
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=== not ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 3: if condition is not true !!
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! if condition is not true !!
 
|-
 
|-
 
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|}  
 
|}  
  
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=== equal to ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
Example 1: if a equals 1 !!
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!  if a equals 1 !!
 
|-
 
|-
 
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|}
 
|}
  
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=== does not equal ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 2: if a does not equal 2 !!
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! if a does not equal 2 !!
 
|-
 
|-
 
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|}
 
|}
  
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=== greater than or equal to ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 3: if a is greater than or equal to 2 !!
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! if a is greater than or equal to 2 !!
 
|-
 
|-
 
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|}
 
|}
  
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=== greater than ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 4: if a is greater than 2 !!
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! if a is greater than 2 !!
 
|-
 
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|}
 
|}
  
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=== less than or equal to ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 5: if a less than or equal to 2  !!
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! if a less than or equal to 2  !!
 
|-
 
|-
 
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|}
  
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=== less than ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 6: if a less than 2  !!
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! if a less than 2  !!
 
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|-
 
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=== add ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 1: 1 +2 = 3 !!
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! 1 + 2 = 3 !!
 
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|}
 
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=== subtract ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 2: 3 - 2 = 1 !!
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! 3 - 2 = 1 !!
 
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=== inverse ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
|-
! Example 3: inversed values !!
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! 3'''inv''' = -3 !!
 
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=== multiply ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
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! Example 4: 2 x 2 = 4 !!
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! 2 x 2 = 4 !!
 
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=== divide ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
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! Example 5: 10 ÷ 5 = 2  !!
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! 10 ÷ 5 = 2  !!
 
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=== power ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
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! Example 6: base of 2, power of 8 (2ⁿ) = 256  !!
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! base of 2, power of 8 (2ⁿ) = 256  !!
 
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=== remainder ===
 
{| class="ts"
 
{| class="ts"
 
|-
 
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! Example 7: remainder of 25 ÷ 4 = 1 !!
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! remainder of 25 ÷ 4 = 1 !!
 
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|-  
 
| style="max-width: 700px;" | <syntaxhighlight>
 
| style="max-width: 700px;" | <syntaxhighlight>

Revision as of 17:44, 25 August 2014

Lua operators are expressions used to perform calculations or to pass arguments between different value types.

< Index >

Conditional Operators

if Query if something does or does not meet a certain condition.
else Do something else if the query condition was not met.
elseif Used to add additional if queries, if the initial query condition was not met.
end This is used to close various queries or functions; there must be the same amount of end as if; except in instances where elseif has been used.

if

if condition is true (method 1)
local a = true

if a then
 print("a = true")
end
click to enlarge
if condition is true (method 2)
local a = true

if a == true then
 print("a = true")
end
click to enlarge
if condition is false
local a = false

if a == false then
 print("a = false")
end
click to enlarge

else

if condition is not met, then do else
local a = false

if a then
 print("a = true")
else
 print("a = false")
end
click to enlarge

elseif

if condition is not met, then do elseif
local a = false

if a then
 print("a = true")
elseif not a then
 print("a = false")
end
click to enlarge

Logical Operators

and Allows you to check multiple conditions in a single if query.
or Allows you to add an alternative if query into a single if query.
not Checks if condition equals false or negative.

and

if condition a is true and condition b is false then
local a = true
local b = false

if a == true and b == false then
 print("a = true", "b=false")
end
click to enlarge

or

if condition is true or condition == true then
local a = true

if a or a == true then
 print("a = true")
end
click to enlarge

not

if condition is not true
local a = false

if not a then
 print("a = false")
end
click to enlarge

Comparison Operators

== Equal to.
~= Does not equal.
>= Greater than or equal to.
> Greater than.
<= Less than or equal to.
< Less than.

equal to

if a equals 1
local a = 1

if a == 1 then
 print("a = 1")
end
click to enlarge

does not equal

if a does not equal 2
local a = 1

if a ~= 2 then
 print("a = " .. a)
end
click to enlarge

greater than or equal to

if a is greater than or equal to 2
local a = 5

if a >= 2 then
 print("a = " .. a)
end
click to enlarge

greater than

if a is greater than 2
local a = 3

if a > 2 then
 print("a = " .. a)
end
click to enlarge

less than or equal to

if a less than or equal to 2
local a = 2

if a <=  2 then
 print("a = " .. a)
end
click to enlarge

less than

if a less than 2
local a = 0

if a <  2 then
 print("a = " .. a)
end
click to enlarge

Mathematical Operators

+ Add
- Subtract or invert
* Multiply
/ Divide
^ Power
% Remainder

add

1 + 2 = 3
local a = 1
local b = 2
local result = a + b

print( result )
click to enlarge

subtract

3 - 2 = 1
local a = 3
local b = 2
local result = a - b

print( result )
click to enlarge

inverse

3inv = -3
local a = 3
local result = -a

print( "original value: " .. a, "inversed value: " .. result )
click to enlarge

multiply

2 x 2 = 4
local a = 2
local result = a * a

print( result )
click to enlarge

divide

10 ÷ 5 = 2
local a = 10
local b = 5
local result = a / b

print( result )
click to enlarge

power

base of 2, power of 8 (2ⁿ) = 256
local a = 2
local b = 8
local result = 2 ^ 8

-- break down power function into string result (ignore this code)
function power(i1, i2)
 local val = ""
 --+--
 for i = 1, i2 do
  if i < i2 then val = val..i1.."*" else val = val..i1 end
 end
 return "which is the equivalent of " .. val
end

print("power value of 2 & 8 = " .. result, power(a,b))
click to enlarge

remainder

remainder of 25 ÷ 4 = 1
local a = 25
local b = 4
local result = a / 4
local remainder = a % b
local decimal = remainder / b

print("result: 25 ÷ 4 = "  .. result, "remainder: .25 x 4 = " .. remainder, "decimal: 1 ÷ 4 = " .. decimal )
click to enlarge
< Index >