No need, you were not rude in any way.
On Tue, Sep 13 2016, Michele Zaffalon wrote:
> Apologies, I did not want to insult or be rude. Thank you again for the
> clear explanation.
>
> On Tue, Sep 13, 2016 at 8:38 AM, Tamas Papp <tkp...@gmail.com> wrote:
>
>> Please don't put words in my mouth, I did not say that. In general, I
>> find "use case" an elusive concept. I prefer simple building blocks with
>> clear semantics that I can combine easily to solve problems.
>>
>> Also, whether something "makes sense" is also somewhat subjective and
>> depends on your expectations and prior experience. Coming from, say,
>> Common Lisp, Julia's semantics in this case make perfect sense. Coming
>> from other languages, you may find it surprising, but that's always part
>> of learning a new language. My own preference is to write quite a bit of
>> code in a language before commenting on whether certain features "make
>> sense", but YMMV.
>>
>> On Tue, Sep 13 2016, Michele Zaffalon wrote:
>>
>> > Thank you for your explanation.
>> >
>> > In practice you are saying that consistency has led to this consequence
>> > even though there is no use case, and therefore it makes little sense? I
>> am
>> > not trying to provoke, it is that I find it easier to internalize the
>> > concept, once I know the reason behind that concept.
>> >
>> >
>> > On Tue, Sep 13, 2016 at 7:24 AM, Tamas Papp <tkp...@gmail.com> wrote:
>> >
>> >> Fill behaves this way not because of a specific design choice based on a
>> >> compelling use case, but because of consistency with other language
>> >> features. fill does not copy, and arrays are passed by reference in
>> >> Julia, consequently you have the behavior described below.
>> >>
>> >> IMO it is best to learn about this and internalize the fact that arrays
>> >> and structures are passed by reference. The alternative would be some
>> >> DWIM-style solution where fill tries to figure out whether to copy its
>> >> first argument or not, which would be a mess.
>> >>
>> >> On Tue, Sep 13 2016, Michele Zaffalon wrote:
>> >>
>> >> > I have been bitten by this myself. Is there a user case for having an
>> >> array
>> >> > filled with references to the same object? Why would one want this
>> >> > behaviour?
>> >> >
>> >> > On Tue, Sep 13, 2016 at 4:45 AM, Yichao Yu <yyc1...@gmail.com> wrote:
>> >> >
>> >> >>
>> >> >>
>> >> >> On Mon, Sep 12, 2016 at 10:33 PM, Zhilong Liu <
>> lzl200102...@gmail.com>
>> >> >> wrote:
>> >> >>
>> >> >>> Hello all,
>> >> >>>
>> >> >>> I am pretty new to Julia, and I am trying to perform push and pop
>> >> inside
>> >> >>> an array of 1D array elements. For example, I created the following
>> >> array
>> >> >>> with 1000 empty arrays.
>> >> >>>
>> >> >>> julia> vring = fill([], 1000)
>> >> >>>
>> >> >>
>> >> >>
>> >> >> This creates an array with 1000 identical object, if you want to make
>> >> them
>> >> >> different (but initially equal) object, you can use `[[] for i in
>> >> 1:1000]`
>> >> >>
>> >> >>>
>> >> >>> Then, when I push an element to vring[2],
>> >> >>>
>> >> >>>
>> >> >>> julia> push!(vring[2],1)
>> >> >>>
>> >> >>>
>> >> >>> I got the following result. Every array element inside vring gets
>> the
>> >> >>> value 1. But I only want the 1 to be pushed to the 2nd array element
>> >> >>> inside vring. Anybody knows how to do that efficiently?
>> >> >>>
>> >> >>>
>> >> >>> julia> vring
>> >> >>>
>> >> >>> 1000x1 Array{Array{Any,1},2}:
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> ⋮
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>> Any[1]
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>> Thanks!
>> >> >>>
>> >> >>> Zhilong Liu
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>
>> >>
>> >>
>>
