Difference between revisions of "Basic lua: Operators"

From The Official Visionaire Studio: Adventure Game Engine Wiki
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|}
  
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{| class="ts"
 +
|-
 +
!  Example 1: 1 +2 = 3 !!
 +
|-
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| <syntaxhighlight>
 +
local a = 1
 +
local b = 2
 +
local result = a + b
  
 +
print( result )
 +
</syntaxhighlight> || width="200px" | [[File:lb_operators_0015.png|thumb|right|180px|click to enlarge]]
 +
|}
 +
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{| class="ts"
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|-
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! Example 2: 3 - 2 = 1 !!
 +
|-
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| <syntaxhighlight>
 +
local a = 3
 +
local b = 2
 +
local result = a - b
 +
 +
print( result )
 +
</syntaxhighlight> || width="200px" | [[File:lb_operators_016.png|thumb|right|180px|click to enlarge]]
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|}
 +
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{| class="ts"
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|-
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! Example 3: inversed values !!
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|-
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| <syntaxhighlight>
 +
local a = 3
 +
local result = -a
 +
 +
print( "original value: " .. a, "inversed value: " .. result )
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</syntaxhighlight> || width="200px" | [[File:lb_operators_017.png|thumb|right|180px|click to enlarge]]
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|}
 +
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{| class="ts"
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|-
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! Example 4: 2 x 2 = 4 !!
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|-
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| <syntaxhighlight>
 +
local a = 2
 +
local result = a * a
 +
 +
print( result )
 +
</syntaxhighlight> || width="200px" | [[File:lb_operators_018.png|thumb|right|180px|click to enlarge]]
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|}
 +
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{| class="ts"
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|-
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! Example 5: 10 ÷ 5 = 2  !!
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|-
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| <syntaxhighlight>
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local a = 10
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local b = 5
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local result = a / b
 +
 +
print( result )
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</syntaxhighlight> || width="200px" | [[File:lb_operators_019.png|thumb|right|180px|click to enlarge]]
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|}
 +
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{| class="ts"
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|-
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! Example 6: base of 2, power of 8 (2ⁿ) = 256  !!
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|-
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| <syntaxhighlight>
 +
local a = 2
 +
local b = 8
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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
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return "which is the equivalent of " .. val
 +
end
 +
 +
print("power value of 2 & 8 = " .. result, power(a,b))
 +
</syntaxhighlight> || width="200px" | [[File:lb_operators_020.png|thumb|right|180px|click to enlarge]]
 +
|}
 +
 +
 +
{| class="ts"
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|-
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! Example 7: remainder of 25 ÷ 4 = 1 !!
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|-
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| <syntaxhighlight>
 +
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 ) 
 +
</syntaxhighlight> || width="200px" | [[File:lb_operators_021.png|thumb|right|180px|click to enlarge]]
 +
|}
 
{{toc}}
 
{{toc}}

Revision as of 13:39, 21 August 2014

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

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.
Example 1: if condition is true (method 1) 
local a = true

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

if a == true then
 print("a = true")
end
click to enlarge
Example 3: if condition is false 
local a = false

if a == false then
 print("a = false")
end
click to enlarge
Example 4: 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
Example 5: 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.
Example 1: 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
Example 2: if condition is true or condition == true then 
local a = true

if a or a == true then
 print("a = true")
end
click to enlarge
Example 3: 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.
Example 1: if a equals 1 
local a = 1

if a == 1 then
 print("a = 1")
end
click to enlarge
Example 2: if a does not equal 2 
local a = 1

if a ~= 2 then
 print("a = " .. a)
end
click to enlarge
Example 3: if a is greater than or equal to 2 
local a = 5

if a >= 2 then
 print("a = " .. a)
end
click to enlarge
Example 4: if a is greater than 2 
local a = 3

if a > 2 then
 print("a = " .. a)
end
click to enlarge
Example 5: if a less than or equal to 2 
local a = 2

if a <=  2 then
 print("a = " .. a)
end
click to enlarge
Example 6: 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
Example 1: 1 +2 = 3 
local a = 1
local b = 2
local result = a + b

print( result )
File:Lb operators 0015.png
click to enlarge
Example 2: 3 - 2 = 1 
local a = 3
local b = 2
local result = a - b

print( result )
click to enlarge
Example 3: inversed values 
local a = 3
local result = -a

print( "original value: " .. a, "inversed value: " .. result )
click to enlarge
Example 4: 2 x 2 = 4 
local a = 2
local result = a * a

print( result )
click to enlarge
Example 5: 10 ÷ 5 = 2 
local a = 10
local b = 5
local result = a / b

print( result )
click to enlarge
Example 6: 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


Example 7: 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


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