In Lua, except that table is passed by reference, the rest are basically passed by value. So when you print a table directly, what you see is a pointer type data.
On the one hand, you cannot copy a table by simply “=”, because it is still its own reference (address) that is passed in this way, and an additional method must be written to realize the copy of the table;
h3>
On the other hand, the table type data returned by the function return is also a return reference. If you want to get the data in a read-only way, you should perform a copy operation after getting it, and then copy it Make modifications;
For other common data types except table, it is basically the way of passing values. The following uses functions as an example:
function fun_1()
print(“first function”)
end
function fun_2()
Print(“second function”)
end
x= fun_1
y=x
x=fun_2
y()
x()
Output: First function Modifying x has no effect on y, which can be seen as a “value transfer” method.
Second function
p>
The following is an example of implementing copy table:
function cloneTable(tab) – Clone a table < /div>
local function copy(target, res)
for k,v in pairs(target) do
if type(v) ~= “table” then < /div>
Res[k] = v;
Else
Res[k] = {};
]) Recursion
end
end end
end
local result = {}
copy(tab, result)
return result
end
function cloneTable(tab ) Clone a table
local function copy(target, res)
for k,v in pairs(target) do
res [k] = v;
else
res [k] = {};
Copy(v, res[k]) – Recursion
End
End
End
local result = {}
copy(tab, result)
return result
end
function cloneTable(tab) – Clone a table
local function copy(target,res)
for k,v in pairs(target)do
If type(v) ~= “table” then
Res[k] = v;
Else
;
copy(v, res[k]) – recursion
end
end
end
local result = {}
copy(tab,result)
return result
end