Hi guys, just a specific question here: I would like to create a data type with several fields, and give a default value to some of them, but not all. But more specifically, I would like to have only this value appear in the new() constructor, something like mutable struct coly8 x :: Int32 …

[image] davidbp: Now I am only missing how to do this for any subset of the fields without specifying the values of the complementary part of the fields. Any ideas? . Are you looking for something like this? mutable struct coly_xy x :: Int32 y :: Float64 z :: Bool t :: Int32 …

Very interesting this discussion about the macro, but that in the end does not solve the problem as you mention. Maybe I would need to write a complex macro for that, but sounds somewhat weird compared to other languages where you can give default values in the structs directly without too much hass…

A related question is: are you sure you want to leave the fields literally undefined? There’s no programmatic way to tell the difference between an ::Int32 field that you left uninitialized and one you filled with a value. Even an uninitialized Int32 will have a value, it’s just an undefined value w…

I was looking for something like this earlier, and went with Union{Int64, Missing}. You can initialize your structure variables with missing values which lets you know precisely which values are missing and take care of them gracefully. Alternatively, you could simply assign a rand() to each variab…

[image] Ferran_Mazzanti: sounds somewhat weird compared to other languages where you can give default values in the structs directly without too much hassle Agree, probably it will be improved in future. Union{Int64, Missing} from answers above should also be shortened to Int64? or similar.

Ok thank you again… I see smart solutions to the problem, butno matter what, you still have to give default values to all variables, at least in the definition of each field with the @kwdef macro as proposed above. Much better than having to state a value for each specific instance and solves the pr…

Hola Ferran :slight_smile: Maybe using a constructor with optional arguments solves your use case? julia> mutable struct Coly1 x :: Int32 y :: Float64 z :: Bool t :: Int32 u :: Float32 v :: Bool end; julia> function Coly1(;x…

I coded many languages and some Julia behaviours are bothering me too, but not this one. Could you tell which language’s behaviour is perfect for you? I recalled when I wrote getters and setter methods in Java there were code generator integrated in IDE for that. Maybe we can go this way and script…

Hi guys (hola Davis :slightly_smiling_face: first thing and to answer the first question: no programming language I have found so far seems perfect for me, all of them have enbeded decisions that you could discuss at least. Stating that “Limitation is not in Julia’s vocabulary” implies that everyth…

[image] Ferran_Mazzanti: krok = croco() > croco(5.0e-324, false) You can set even set the constructor inside the struct so that you have this behaviour julia> mutable struct croco2 x :: Float64 y :: Bool croco2(;x=1,y=false) = new(x,y) end julia> croco2(x=2…

[image] Ferran_Mazzanti: I would like to have only this value appear in the new() constructor I might be misunderstanding something but isn’t the whole problem that you failed to return the object from the constructor? This seems to do what you want. mutable struct coly8 x :: Int32 y…

Default value of some fields in a mutable struct

General Usage

Jakub_Wronowski January 16, 2020, 1:00pm 19

Awesome! It can be wrapped into a macro for nicer syntax. Great solution.

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Default value of *some* fields in a mutable struct

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Default value of some fields in a mutable struct