Boolean: Difference between revisions
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===And=== | ===And=== | ||
{{main|and operator}} | |||
The '''and''' operator returns the first argument if it is false or [[nil]], otherwise it will return the second argument. | The '''and''' operator returns the first argument if it is false or [[nil]], otherwise it will return the second argument. | ||
Revision as of 22:39, 29 January 2012
A Boolean, or Bool value, is a very simple data type. It is either a true or false value.
In Lua, when something is converted to a boolean, if the value is false or nil then it will be false, otherwise it is true.
Using Boolean's
Booleans are most commonly used with conditional statements
MyBool = true
if MyBool then
--If "MyBool"'s value is true, this code is run.
else
--If "MyBool"'s value is false, this code is run.
end
Converting booleans into strings
When converted to a string, booleans will return "true" or "false"
If you wanted it to print something other than true or false, you will have to use a conditional statements
local enabled = false
if enabled then
print("Enabled")
else
print("Disabled")
end
However, there is a cleaner way of doing this. You can use the following idiom:
print(enabled and "Enabled" or "Disabled")
and get the same results.
Operators
Not
The not operator returns true if the argument is false or nil, otherwise it will return false.
print(not false) -- true
print(not nil) -- true
print(not true) -- false
print(not "A string") -- false
print(not 0) -- false
print(not 1) -- false
And
The and operator returns the first argument if it is false or nil, otherwise it will return the second argument.
print(4 and 5) --> 5
print(nil and 13) --> nil
print(false and 13) --> false
print(true and true) -- true
print(true and false) -- false
print(false and true) -- false
print(false and false) -- false
Or
The or operator returns the first argument if it is neither false nor nil, otherwise it will return the second argument.
print(true or true) -- true
print(true or false) -- true
print(false or true) -- true
print(false or false) -- false
print(4 or 5) --> 4
print(false or 5) --> 5
