Question About copy Tables

[startup]

tabl1 = {9,5,8,1,6,0}
tabl2 = tabl1  -- make a copy of tabl1 befor sorting

Table.Sort(tabl1, nil); -- sort tabl1

result1 = Table.Concat(tabl1, " - ", 1, TABLE_ALL);
result2 = Table.Concat(tabl2, " - ", 1, TABLE_ALL);

Dialog.Message("Notice", result1.."\r\n"..result2, MB_OK, MB_ICONINFORMATION, MB_DEFBUTTON1);

Now both Tables are sorted
0-1-5-6-8-9
what sort the copy of the origenal table (tabl2) ?????
what sort tabl2 in my code ?????

[startup]

i mean
why tabl2 get sorted ???

[Ulrich]

Read the documentation.

Ulrich

[startup]

thnaks Ulrich
i know that

did tabl1 = tabl2 makes a copy ??
or make a relative copy ??

[Ronin]

Here:

tabl1 = {9,5,8,1,6,0};
tabl2 = {};

for i=1, #tabl1 do
	tabl2[i] = tabl1[i];
end

result1 = Table.Concat(tabl1, " - ", 1, TABLE_ALL);
result2 = Table.Concat(tabl2, " - ", 1, TABLE_ALL);

Dialog.Message("Notice", result1.."\r\n"..result2, MB_OK, MB_ICONINFORMATION, MB_DEFBUTTON1);

[startup]

thanks Ronin
same as

for a,z in pairs (tabl1) do
	tabl2[a] = tabl1[a];
end

still confuse about
tbl2 = tbl1
why tbl2 clanging when we change tbl1 ??

ok
never mind
thanks all

[startup]

sory
why tbl2 changes when we change tbl1 ??

[Ronin]

That's because 'tbl2 = tbl1' doesn't actually create a whole new table, it just links tbl2 to tbl1.

In a way, it's like domains and hosts. You can create multiple domains (google.com, google.co.uk, google.fr) and link them to the same host.

[startup]

Link 2 tables ??

ok

tbl1=tbl2

is a negative picture of the compare function :-

if tbl1==tbl2 then
--do some thing
end

EXAMPLES

not equal example

tabl1 = {9,5,8,1,6,0};
tabl2 = {4,5,8,1,6,4};

if tabl1==tabl2 then
 Dialog.Message("Notice", "equal", MB_OK, MB_ICONINFORMATION, MB_DEFBUTTON1);
 else
 Dialog.Message("Notice", "not equal", MB_OK, MB_ICONINFORMATION, MB_DEFBUTTON1) 
end

you got "not equal"

the equal example

tabl1 = {9,5,8,1,6,0};
tabl2 = {9,5,8,1,6,0};

if tabl1==tabl2 then
 Dialog.Message("Notice", "equal", MB_OK, MB_ICONINFORMATION, MB_DEFBUTTON1);
 else
 Dialog.Message("Notice", "not equal", MB_OK, MB_ICONINFORMATION, MB_DEFBUTTON1) 
end

you got "equal"

[Imagine Programming]

tabl1 = {9,5,8,1,6,0};
tabl2 = tabl1;

The code above simply only copies the reference to the table, not the contents. Sorting or modifying table 1 will also modify table 2.

[startup]

thanks Imagine Programming for Explain

[startup]

tabl1 = {9,5,8,1,6,0};
tabl2 = tabl1;

The code above simply only copies the reference to the table, not the contents. Sorting or modifying table 1 will also modify table 2.

then how can i explain this ??

Table1 = {1,2,3,4,5,6,7,8,9,10}
Table2 = Table1
Table1={}
concated1 = Table.Concat(Table1, " , ", 1, TABLE_ALL);
concated2 = Table.Concat(Table2, " , ", 1, TABLE_ALL);
Dialog.Message("Notice", concated1);
Dialog.Message("Notice", concated2);

[Imagine Programming]

1. You create a table with all numbers from 1 to and including 10 and set the reference to it in the variable Table1.
2. You copy the reference to that table to the variable Table2
3. You create a new table with nothing in it and set the reference to it in the variable Table1
4. You concatenate Table 1 with comma's in between
5. You concatenate Table 2 with comma's in between
6. You display the concatenated version of Table1 in a message box, which should display an empty string
7. You display the concatenated version of Table2 in a message box, which should display the first table.

What is happening here, is that you copy the reference of the table in Table1 to Table2. You then overwrite Table1 with a new reference to a new table.

This means that the original table still has a reference (in Table2) so it will not have the garbage collector clean it up, it exists via Table2. Table1 however
does not have a reference to it anymore, so it now points to an empty table.

[startup]

thanks Imagine Programming
that was so clear

[Imagine Programming]

thanks Imagine Programming
that was so clear

You're welcome, good to hear!