Insert multivalue into lua table

Solar2D Lua Language
#1

Hi all,

Trying to convert a JavaScript game into lua, and found this command:

_aTilesMc.push(new CTile(i,aPos[i],szRandValue,aLeftBlocks[i],aRightBlocks[i],aUpBlocks[i],aBlockingList[i],aTileHeight[i]));

 _aTilesMc is an array (table in lua) and push is like insert an element into it.

Dunno what CTile is, but how do you add a new multi value element into a table like this?

Also:

aTilesMc[i].init(pPos);

Can’t find an ‘init’ command in JavaScript for arrays, so not sure what init does?

#2

CTile is a JavaScript object.  You would need to find the code for it to see what it’s new/init function does.

table.insert() would be similar to the push action.  Push sounds to me like it inserts it in the 1st position of the table.

Rob

#3

Thanks Rob.

how do you add a new multi value element into a table?

table.insert(Table,{value1,value2,value3})

??

#4

See:  http://docs.coronalabs.com/api/library/table/insert.html

table.insert( yourTable, yourObjectOrValue) will insert the new item at the end of the table, which is the same as:

yourTable[#yourTable+1] = yourObjectOrValue

If you want to insert the item in the middle of the table or at the begging you can specify a position #:

table.insert( yourTable, 1, yourObjectOrValue )   – inserts it at the front of the table

Rob

#5

How about this, any javascript programmers over here?

JavaScript:

var \_aUpBlocks = new Array(); var \_aLeftBlocks = new Array(); var \_aRightBlocks = new Array(); \_aUpBlocks[0] = [];\_aLeftBlocks[0] = [];\_aRightBlocks[0] = []; \_aUpBlocks[1] = [];\_aLeftBlocks[1] = [0];\_aRightBlocks[1] = [2];

I translated this code into Lua like:

\_aUpBlocks = {} \_aLeftBlocks = {} \_aRightBlocks = {} \_aUpBlocks[0] = {};\_aLeftBlocks[0] = {};\_aRightBlocks[0] = {}; \_aUpBlocks[1] = {};\_aLeftBlocks[1] = 0;\_aRightBlocks[1] = 2;

But translating **_aUpBlocks[0] = [] to _aUpBlocks[0] = {} **doesn’t seem to be correct, it expects a numeric value.

#6

JavaScript programmer here :slight_smile:

First off, you should probably index your arrays with 1, as that’s how Lua does it. That means all your array indices will be incremented by one. So _aUpBlocks[1] -> _aUpBlocks[2], etc.

Second, you’re setting _aLeftBlocks[1] to the number 0, rather than an array with the number 0 inside it. Same goes for _aRightBlocks[1].

\_aLeftBlocks[1] = {0}

And the semicolons are completely unneeded in Lua. Lua doesn’t have semicolon troubles.

  • Caleb
#7

Thanks,

Yeah I already noticed indexing to 1 is common in Lua.

But what does

_aLeftBlocks[0] = []

exactly do in Javascript?

_aLeftBlocks[0] = {} doesn’t seem to be a correct translation as Lua expects a number value?

#8

_aLeftBlocks[0] = [] in JavaScript means “set element #1 in the _aLeftBlocks array to an empty array”.

What do you mean by “Lua expects a number value”?

  • Caleb
#9

Ok, so _aLeftBlocks[0] = {} is the correct translation from _aLeftBlocks[0] = [] in JavaScript?

If yes, I will figure out the rest :slight_smile: Thanks again.

#10

Technically, yes. But, like I said, JavaScript uses 0 as the first element in an array, while Lua uses 1. A “semantic” translation would change the 0s to 1s and the 1s to 2s etc.

  • Caleb
#11

CTile is a JavaScript object.  You would need to find the code for it to see what it’s new/init function does.

table.insert() would be similar to the push action.  Push sounds to me like it inserts it in the 1st position of the table.

Rob

#12

Thanks Rob.

how do you add a new multi value element into a table?

table.insert(Table,{value1,value2,value3})

??

#13

See:  http://docs.coronalabs.com/api/library/table/insert.html

table.insert( yourTable, yourObjectOrValue) will insert the new item at the end of the table, which is the same as:

yourTable[#yourTable+1] = yourObjectOrValue

If you want to insert the item in the middle of the table or at the begging you can specify a position #:

table.insert( yourTable, 1, yourObjectOrValue )   – inserts it at the front of the table

Rob

#14

How about this, any javascript programmers over here?

JavaScript:

var \_aUpBlocks = new Array(); var \_aLeftBlocks = new Array(); var \_aRightBlocks = new Array(); \_aUpBlocks[0] = [];\_aLeftBlocks[0] = [];\_aRightBlocks[0] = []; \_aUpBlocks[1] = [];\_aLeftBlocks[1] = [0];\_aRightBlocks[1] = [2];

I translated this code into Lua like:

\_aUpBlocks = {} \_aLeftBlocks = {} \_aRightBlocks = {} \_aUpBlocks[0] = {};\_aLeftBlocks[0] = {};\_aRightBlocks[0] = {}; \_aUpBlocks[1] = {};\_aLeftBlocks[1] = 0;\_aRightBlocks[1] = 2;

But translating **_aUpBlocks[0] = [] to _aUpBlocks[0] = {} **doesn’t seem to be correct, it expects a numeric value.

#15

JavaScript programmer here :slight_smile:

First off, you should probably index your arrays with 1, as that’s how Lua does it. That means all your array indices will be incremented by one. So _aUpBlocks[1] -> _aUpBlocks[2], etc.

Second, you’re setting _aLeftBlocks[1] to the number 0, rather than an array with the number 0 inside it. Same goes for _aRightBlocks[1].

\_aLeftBlocks[1] = {0}

And the semicolons are completely unneeded in Lua. Lua doesn’t have semicolon troubles.

  • Caleb
#16

Thanks,

Yeah I already noticed indexing to 1 is common in Lua.

But what does

_aLeftBlocks[0] = []

exactly do in Javascript?

_aLeftBlocks[0] = {} doesn’t seem to be a correct translation as Lua expects a number value?

#17

_aLeftBlocks[0] = [] in JavaScript means “set element #1 in the _aLeftBlocks array to an empty array”.

What do you mean by “Lua expects a number value”?

  • Caleb
#18

Ok, so _aLeftBlocks[0] = {} is the correct translation from _aLeftBlocks[0] = [] in JavaScript?

If yes, I will figure out the rest :slight_smile: Thanks again.

#19

Technically, yes. But, like I said, JavaScript uses 0 as the first element in an array, while Lua uses 1. A “semantic” translation would change the 0s to 1s and the 1s to 2s etc.

  • Caleb