Thanks Cameron.
What I wanted to do was assign values to fields but the example you posted
requires me to pass values to all fields in my type.
If I do: events[1] = ExampleEvent("asdf",123), julia throws an error since
I need to pass values to ALL my type's fields. I don't always have to use
all fields & sometimes do not have data for all fields, thus I don't want
to be obligated to pass even null values to them since it is
verbose/excessive. Nor do I want to rewrite constructors for all fields
since I already have named fields for sake of programming ease.
See what I mean?
Moreover, let's say I've filled 10 elements of my 1000 element array & a
few milliseconds later I get a value for element 5, fld3. How do I index
into element 5 of the events Vector & ONLY set fld3?
Yes I've seen push! & looks good but I'm pretty religious about
precallocating in any lang even if it is much larger than needed since
processing these datasets require as much efficiency as possible.
I think more intuitive Composite Type Arrays for morons like me would make
Juila much easier to work with since I've seen a fair amount of
uncertainty/confusion from people having similar conceptual use cases. I
know I'm thinking from a perspective of other language(s) but some language
constructs are there because they work & make a programmer's life easier.
Is there an easy way to set field value(s) whenever I get them?
On Friday, July 22, 2016 at 2:01:41 PM UTC-4, Cameron McBride wrote:
>
> Your ExampleEvent is completely analagous to a C-like struct. With
> Stefan's bit, you now have a single dimension array of ExampleEvent type
> (hence ndims(events) is 1).
>
> You can do this:
> julia> events[1] = ExampleEvent("asdf",2,3,4,5,6,7)
> ExampleEvent("asdf",2,3,4,5,6,7)
>
> And if you have more, you can do this:
> julia> push!(events, ExampleEvent("ghjk", 2,3,4,5,6,7))
> 1001-element Array{ExampleEvent,1}:
> ExampleEvent("asdf",2,3,4,5,6,7)
> #undef
> ⋮
> #undef
> ExampleEvent("ghjk",2,3,4,5,6,7)
>
> Cameron
>
> On Fri, Jul 22, 2016 at 1:48 PM, <[email protected] <javascript:>> wrote:
>
>> Thanks Stefan!
>>
>> I thought it would be like declaring a struct array in c/c++ i.e.
>> something like ExampleEvent events[2][1000]; Then set each field in the
>> events array as I encounter the required value in my algo: e.g.
>> events[1][1].fld1 = "ABC"; events[1][1].fld2 = 123; etc
>>
>> How do I access elements in the events Vector since ndims(events) = 1? I
>> don't see anything in the docs about indexing into a preallocated Vector
>> data structure. I see methods like push! splice! etc but not anything that
>> will let me use the elements of my preallocation on the fly.
>>
>>
>> On Thursday, July 21, 2016 at 3:21:54 PM UTC-4, Stefan Karpinski wrote:
>>>
>>> It's a little unclear what you want to do that you can't figure out how
>>> to accomplish. You can allocate an uninitialized vector of ExampleEvent
>>> objects:
>>>
>>> julia> type ExampleEvent
>>> fld1::ASCIIString
>>> fld2::Int16
>>> fld3::Int64
>>> fld4::Int64
>>> fld5::Int64
>>> fld6::Int64
>>> fld7::Int64
>>> end
>>>
>>> julia> events = Vector{ExampleEvent}(1000)
>>> 1000-element Array{ExampleEvent,1}:
>>> #undef
>>> #undef
>>> #undef
>>> ⋮
>>> #undef
>>> #undef
>>> #undef
>>>
>>>
>>>
>>>
>>> On Thu, Jul 21, 2016 at 2:51 PM, <[email protected]> wrote:
>>>
>>>>
>>>> Hi
>>>>
>>>> I was working on processing large data sets & historically I've used
>>>> structs in C++ & other languages for this type of task. I attempted to use
>>>> a Composite Type in Julia & preallocate a large array before filling it
>>>> w/values as my algo processes the data.
>>>>
>>>> My example was:
>>>>
>>>> type ExampleEvent
>>>>
>>>> fld1::ASCIIString
>>>> fld2::Int16
>>>> fld3::Int64
>>>> fld4::Int64
>>>> fld5::Int64
>>>> fld6::Int64
>>>> fld7::Int64
>>>>
>>>> end
>>>>
>>>> I googled around & from what I found, & all the docs examples I tried
>>>> out, there isn't an obvious way to declare an array of composite type
>>>> without having to do some work arounds.
>>>>
>>>> I liked the language in several other respects but it seems to be
>>>> missing helpful tools to make the programmer's life easy. Am I missing
>>>> something? If not, why is a data structure like this not easily available?
>>>>
>>>> thanks in advance
>>>>
>>>> best,
>>>> A
>>>>
>>>
>>>
>
