nil
nil is Lua's representation of empty data. Unset variables and non-existent table keys will be nil. This will be treated as false in if-statement contexts, but is not equal to false.
Example
print( nil )
print( nil == 0 )
print( nil == 1 )
print( nil == nil )
print( !nil ) -- because nil can be treated like a false boolean in some cases, "not nil" will equal true
local myEmptyVariable -- a variable with nothing in it (a 'nil' value)
print( myEmptyVariable )
local myTable = { a = "foo", b = "bar" }
myTable["a"] = nil -- setting a value in a table to nil effectively erases it from the table
PrintTable( myTable )
Output:
nil
false
false
true
true
nil
b = bar
nil
false
false
true
true
nil
b = bar
Application in VGUI
You can use nil to make some VGUI element transparent.
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