Use `global a = ...`
Please see:
http://docs.julialang.org/en/latest/manual/variables-and-scoping/#hard-local-scope
global variables are only inherited for reading but not for writing
On Fri, Sep 23, 2016 at 12:00 AM, K leo <cnbiz...@gmail.com> wrote:
> Sorry, this is not related to Dict at all. If I replace the "a=get..."
> statement with simply "a=2", the global variable is no longer accessible.
> What is wrong?
>
>
> On Friday, September 23, 2016 at 11:52:24 AM UTC+8, K leo wrote:
>>
>> Calling "get" anywhere in a function makes a global variable undefined.
>> Can anyone please help explaining the following?
>>
>> 1) without calling "get", the global variable is fine:
>>
>> a=0
>>>
>>> Dicta = Dict{Int,Int}()
>>>
>>> function testGlobal()
>>>
>>> println(a)
>>>
>>> merge!(Dicta, Dict(1=>1))
>>>
>>> # a=get(Dicta, 1, 0)
>>>
>>> println(a)
>>>
>>> nothing
>>>
>>> end
>>>
>>>
>>> julia> testGlobal()
>> 0
>> 0
>>
>> 2) calling "get" (same code as above except uncommenting the "get"
>> statement) and the global variable becomes undefined:
>>
>> a=0
>>>
>>> Dicta = Dict{Int,Int}()
>>>
>>> function testGlobal()
>>>
>>> println(a)
>>>
>>> merge!(Dicta, Dict(1=>1))
>>>
>>> a=get(Dicta, 1, 0)
>>>
>>> println(a)
>>>
>>> nothing
>>>
>>> end
>>>
>>>
>>> julia> testGlobal()
>> ERROR: UndefVarError: a not defined
>> in testGlobal() at /xxx/testType.jl:4
>>
>> 3) not calling the first println, the code works, but the global a is not
>> set:
>>
>> a=0
>>>
>>> Dicta = Dict{Int,Int}()
>>>
>>> function testGlobal()
>>>
>>> # println(a)
>>>
>>> merge!(Dicta, Dict(1=>1))
>>>
>>> a=get(Dicta, 1, 0)
>>>
>>> println(a)
>>>
>>> nothing
>>>
>>> end
>>>
>>>
>>>
>> julia> testGlobal()
>> 1
>>
>>
>>
