How to copy a table, but only with specific entries?

Solar2D General Questions/Discussion
#1

I’m making a copy of a table, and I want the new table to only use a specific subset of the original. What I’m not sure is how that would work in LUA language?

local newTable={} for i=1,50 and otherTable[i].Job="Shopkeep" do newTable[i]= { name=otherTable[i].Name, Job="Shopkeep" } end

Pretty simple, right? I want to iterate 50 times to fill my table, but I only want to pick entries from the original table that have job=“Shopkeep”. Essentially, I want to create job-specific tables so that I can browse them using the “tabs” (AKA widget.newSegmentedControl)

The problem is, my syntax appears to be quite clearly wrong…

Any ideas? :slight_smile: [import]uid: 41884 topic_id: 13769 reply_id: 313769[/import]

#2

i think it should be as below…
[lua]local newTable={}
for i=1,50,1 do
if otherTable[i].Job == “Shopkeep” do
newTable[i]= { name=otherTable[i].Name, Job=“Shopkeep” }
end
end[/lua] [import]uid: 71210 topic_id: 13769 reply_id: 50580[/import]

#3

Trying to figure out if I can adapt your code…

for i=1,50,1 do

Why specify three numbers? (Admittedly my syntax knowledge of ‘for’ is terrible…)

if otherTable[i].Job == "Shopkeep" do

‘do’ crashes the build. ‘then’ seems to work in it’s place.

Apart from that, I’m still trying to troubleshoot getting this to work. That being said, I think that the widgets do not tolerate missing spaces in a table (ie: [1][2][3] are fine but [1][3][5] are not) so I guess I need to find another approach where I can fill all of the slots of the new table.

ie: if given this table;

otherTable[1] = { name="Jim", Job="Hunter"} otherTable[2] = { name="Joe", Job="Drinker"} otherTable[3] = { name="Jed", Job="Drinker"}

…and trying to make a new table only out of the “Drinker” jobs, I’d need Joe to become [1] and Jed to become [2]. I think what might be failing it right now is that the entries are made but it’s [1][17][24], etc…

[import]uid: 41884 topic_id: 13769 reply_id: 50656[/import]

#4

sorry that was a typo…

the for loop should have 3 numbers but last number will default to 1 if not given so it will work with 2 values also. 3rd value specify the increment.
ie if we give 2 it will increment by 2
[lua]for 1=1,9,2 do
print(i)
end[/lua]

will print 1 3 5 7 9

so for your issue try doing this
[lua]local newTable={}
local j =1
for i=1,50,1 do
if otherTable[i].Job == “Shopkeep” then
newTable[j]= {name=otherTable[i].Name, Job=“Shopkeep”}
j = j + 1
end
end[/lua] [import]uid: 71210 topic_id: 13769 reply_id: 50674[/import]

#5

Yeah! That works. I had something similar but just couldn’t get the [j]'s and [i]'s on the same page.

However, it had one major bug left which I just figured out. Nothing wrong with your code example, but something for anybody listening that wants to use widget.newTableView()

  1. Using the above code you would now have newTable{}. But you can’t tap anything without having an onRelease=command entry in each table ID!

  2. Okay, so I’ll just add the onRelease entry. Sorry! if you do this:

onRelease = PressingtheButton

…The table generator will just fill in nil as the entry. This means you need to have your onRelease function defined first. This is a problem, particularly because if you’re developing anything on the iPad, that function NEEDs to know the table is there first. (I tried declaring the table first but that didn’t seem to be enough.)

  1. To get past these conflicting problems, you need to use this order:
    a. Define the table
    b. Define the onRelease function
    c. Inject the onRelease entry into the table.

Example:

for i=1,table.maxn(newTable) do newTable[i].onRelease = PressingtheButton end

Using table.maxn() is crucial , because if you just declare a number instead, it will go ahead and make extra table entries up to that number, each one only including onRelease…which is enough to crash widget.newTableView()

Thanks again, renvis! [import]uid: 41884 topic_id: 13769 reply_id: 50695[/import]