What is the best way to check for a nil value in Lua?
A note on true and false in Lua: Lua is special because the only things it considers 'false' are nil and false. In Lua, the number 0 is true, and an empty string "" is also true. In Lua, the number …
Lua: What's the difference between null and nil? - Stack Overflow
2015年7月9日 · nil is a value in the Lua language. null is a variable name. What value does it contain? You can easily check that. We cannot. If it turns out to be nil, then using null is …
Check if a string isn't nil or empty in Lua - Stack Overflow
2013年10月30日 · Lua strings maintain their length internally, so you wouldn't have to count characters. But Lua also interns strings, so checking for equality doesn't require looking at …
concatenation - Lua: Is there a way to concatenate "nil" values ...
2011年11月8日 · Lua: String is nil after explicitly checking for nil. 8. how to represent nil in a table. 4. Lua ...
In Lua, how to set a nil parameter to some default value correctly?
2015年3月22日 · If x/y/z is nil, x/y/z is set to true/1234/"default". Otherwise, it remains whatever it is. Therefore, I have such a line in many places to set a parameter to some default value in …
lua - How to check if a table element is nil - Stack Overflow
2014年12月18日 · You can use some Lua magic and rewrite Etan Reisner's comment as. local E = {} local my_val = ((frameActions or E).action or E).c if my_val ~= nil then --your code here …
null - Lua conditionals on nil types - Stack Overflow
2017年10月24日 · In Lua, these are selection operators, with short-circuit evaluation. false and nil are "falsey"; Any other value is "truthy." Except for "falsey", the operand types don't matter and …
"attempt to index a nil value"-error in Lua - Stack Overflow
You're not returning anything from your function call. Also, use local variables inside functions.. function newImage(Image, posx, posy) local pic = Bitmap.new(Texture.new(Image)) stage: …
How to check if a value is empty in Lua? - Stack Overflow
2012年4月26日 · The variable x is "empty", it is initialized to "nil". (Not the text "nil", but an enumerated value that indicates that the variable is unassigned. In Lua that is defined as nil, in …
lua - attempt to index a nil value (global 'GLOBAL ... - Stack Overflow
2021年5月30日 · According to Lua GLOBAL is a global nil value. That means that there is neither a local variable nor a global variable with that name. Hence you are not allowed to index it …