Difference between revisions of "Basic lua: Operators"
From The Official Visionaire Studio: Adventure Game Engine Wiki
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| − | | class="i_norm" | '''[[basic_lua|Index]]''' | + | | class="i_norm" | '''[[basic_lua:_Index|Index]]''' |
| − | | class="i_arrow" | [[basic_lua: | + | | class="i_arrow" | [[basic_lua:_Types|>]] |
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== Conditional Operators == | == Conditional Operators == | ||
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| − | | class="i_norm" | '''[[basic_lua|Index]]''' | + | | class="i_norm" | '''[[basic_lua:_Index|Index]]''' |
| − | | class="i_arrow" | [[basic_lua: | + | | class="i_arrow" | [[basic_lua:_Types|>]] |
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{{toc}} | {{toc}} | ||
Revision as of 23:34, 21 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. |
| Example 1: if condition is true (method 1) | |
|---|---|
local a = true
if a then
print("a = true")
end |
| Example 2: if condition is true (method 2) | |
|---|---|
local a = true
if a == true then
print("a = true")
end |
| Example 3: if condition is false | |
|---|---|
local a = false
if a == false then
print("a = false")
end |
| Example 4: if condition is not met, then do else | |
|---|---|
local a = false
if a then
print("a = true")
else
print("a = false")
end |
| 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 |
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 |
| Example 2: if condition is true or condition == true then | |
|---|---|
local a = true
if a or a == true then
print("a = true")
end |
| Example 3: if condition is not true | |
|---|---|
local a = false
if not a then
print("a = false")
end |
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 |
| Example 2: if a does not equal 2 | |
|---|---|
local a = 1
if a ~= 2 then
print("a = " .. a)
end |
| Example 3: if a is greater than or equal to 2 | |
|---|---|
local a = 5
if a >= 2 then
print("a = " .. a)
end |
| Example 4: if a is greater than 2 | |
|---|---|
local a = 3
if a > 2 then
print("a = " .. a)
end |
| Example 5: if a less than or equal to 2 | |
|---|---|
local a = 2
if a <= 2 then
print("a = " .. a)
end |
| Example 6: if a less than 2 | |
|---|---|
local a = 0
if a < 2 then
print("a = " .. a)
end |
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 ) |
| Example 2: 3 - 2 = 1 | |
|---|---|
local a = 3
local b = 2
local result = a - b
print( result ) |
| Example 3: inversed values | |
|---|---|
local a = 3
local result = -a
print( "original value: " .. a, "inversed value: " .. result ) |
| Example 4: 2 x 2 = 4 | |
|---|---|
local a = 2
local result = a * a
print( result ) |
| Example 5: 10 ÷ 5 = 2 | |
|---|---|
local a = 10
local b = 5
local result = a / b
print( result ) |
| 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)) |
| 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 ) |
| < | Index | > |
