Iterating over arrays & collections

[gcaplan]

Bit of a dim newbie question, but I can't see anything in the docs or archives.

What is the accepted Xbasic idiom for iterating over the values of arrays and collections?

I can see a couple of ways of hacking it, but nothing as elegant as the iterators in, say PHP or Python.

If Alpha is reading this, might be a good idea to add a section about this to the Array section in the docs...

[Peter.Greulich]

RE: Iterating over arrays & collections

Maybe I'm misunderstanding you, but there is tons of stuff on both Arrays and Collections in the help files. If you are using the CHM file, type either term in the index and hit enter. There's a lot there.

[gcaplan]

RE: Iterating over arrays & collections

I finally found the FOR EACH construct.

It's rather well hidden in the docs...

[AaronBBrown]

RE: Iterating over arrays & collections

Well, I wouldn't exactly say it was hidden...all you have to do is go to the index and type "For Each" :)

We also have the *for_each() function which will iterate over arrays as well as strings.

[gcaplan]

RE: Iterating over arrays & collections

Aaron - it's easy to find it if you know what you're looking for!

I think it's pretty much standard in manuals dealing with arrays to have a section on how to iterate over the values.

My suggestion would be to add a new section to the Arrays and Collections chapter of the Xbasic Reference giving examples of the different approaches.

[AaronBBrown]

RE: Iterating over arrays & collections

I'll let Ed know....

[gcaplan]

RE: Iterating over arrays & collections

Thanks for listening. It's just a suggestion - but I do think it's an omission from the docs that's worth tidying up...

[Jim Chapman]

RE: Iterating over arrays & collections

Hello Aaron,

I like to use the *for_each() function as it is very very fast compared to the 'standard' for each construct. But I have not been able to use it on pointer arrays with a character property, such as:

dim va[5] as p
va[1].name = "Larry"
va[2].name = "Sue"
va[3].name = "Toby"
va[4].name = "Bob"
va[5].name = "Mary"

vList = *for_each(x,"Dear "+x,va[].name)

Can we use *for_each() with pointer arrays ?

Thanks,
Jim

[Steve Andrews]

RE: Iterating over arrays & collections

vList = *for_each(x,"Dear "+x.name,va)
?vlist
= Dear Larry
Dear Sue
Dear Toby
Dear Bob
Dear Mary

[Stan Mathews]

RE: Iterating over arrays & collections

Or

vList = *for_each(x,"Dear "+x,va.dump_properties("name"))
? vlist
= Dear Larry
Dear Sue
Dear Toby
Dear Bob
Dear Mary

[AaronBBrown]

RE: Iterating over arrays & collections

Try this...

dim va[5] as p
va[1].firstname = "Larry"
va[1].lastname = "Jones"
va[2].firstname = "Sue"
va[2].lastname = "Brown"
va[3].firstname = "Toby"
va[3].lastname = "Smith"
va[4].firstname = "Bob"
va[4].lastname = "Saget"
va[5].firstname = "Mary"
va[5].lastname = "Johnson"


vList = *for_each(x,"Dear "+x.firstname + " " + x.lastname,va)
? vlist
= Dear Larry Jones
Dear Sue Brown
Dear Toby Smith
Dear Bob Saget
Dear Mary Johnson

[Stan Mathews]

RE: Iterating over arrays & collections

Just quit showing off, will you?

[Jim Chapman]

RE: Iterating over arrays & collections

Thanks Steve,

That makes sense, but I would not have thought about that syntax.

Thanks,
Jim

[Jim Chapman]

RE: Iterating over arrays & collections

Thanks Stan,

I would not have thought about doing this either, pretty neat, might be some other uses for this.

Thanks,
Jim

[AaronBBrown]

RE: Iterating over arrays & collections

If you look in the most recent release notes, you'll see a note about this...Cian added this feature when he initially wrote *For_each(), but neglected to inform us about it until just a couple weeks ago. :)