That's because ifelse is just a function, not an operator with special
syntax. The ternary operator is just a one-line form of the if-else and
requires the condition to be a single boolean value. It is a genuine
control flow construct, not a function.
On Fri, Jun 6, 2014 at 11:54 PM, David Einstein <dei...@gmail.com> wrote:
> It looks like you have vectorized ifelse, the operator version just
> doesn't work. This code is on line 379 of operators.jl
>
> function ifelse(c::AbstractArray{Bool}, x, y)
> reshape([ifelse(ci, x, y) for ci in c], size(c))
> end
>
> If I do
>
> ifelse((1:10 .< 5) , 1 , 0)
>
> then everything works.
>
> however
>
> (1:10 .< 5) ? 1 : 0
>
> does not. I'm not sure why.
>
> Also it appears that ifelse is not automatically imported like the rest of
> the operators from base are.
>
>
> On Friday, June 6, 2014 10:58:10 PM UTC-4, Stefan Karpinski wrote:
>
>> We should probably vectorize the ifelse function.
>>
>> On Jun 6, 2014, at 10:51 PM, David Einstein <dei...@gmail.com> wrote:
>>
>> sqrt(x.^2 .+ y.^2) .< radius
>> is a vector of booleans
>>
>> ?:
>> expects a boolean
>>
>> you probably want something like:
>>
>> inside_disc(x,y,radius) = map(good -> good ? 1 : 0,
>> sqrt(x.^2+y.^2).<radius)
>>
>>
>>
>> On Friday, June 6, 2014 10:18:36 PM UTC-4, Zahirul ALAM wrote:
>>>
>>> When I pass two arrays the function returns:
>>>
>>>
>>> type: non-boolean (BitArray{1}) used in boolean context while loading
>>> In[10], in expression starting on line 1
>>>
>>>
>>>
>>> I have modified the function to address the element wise operation as
>>> follows:
>>>
>>>
>>> inside_disc(x,y,radius) = sqrt(x.^2 .+ y.^2) .< radius ? 1 : 0
>>>
>>> seems to me that the error is being thrown by .< operation. What am I
>>> missing?
>>>
>>>
>>> On Friday, 6 June 2014 20:34:22 UTC-4, Miguel Bazdresch wrote:
>>>>
>>>> I'm not sure I understand the question. Do you mean something like this?
>>>>
>>>> inside_disc(x,y,radius) = sqrt(x^2+y^2)<radius ? 1 : 0
>>>>
>>>> -- mb
>>>>
>>>>
>>>> On Fri, Jun 6, 2014 at 8:28 PM, Zahirul ALAM <zahiru...@gmail.com>
>>>> wrote:
>>>>
>>>>> I guess one can do a for loop. But how do I vectorize the code?
>>>>>
>>>>>
>>>>> On Friday, 6 June 2014 20:27:46 UTC-4, Zahirul ALAM wrote:
>>>>>>
>>>>>> How would one implement a step function like behaviour in julia? In
>>>>>> mathematica one can write the following to create a circle with value of
>>>>>> 1
>>>>>> within the radius and 0 outside
>>>>>>
>>>>>> UnitBox[Sqrt[X^2 + Y^2]*0.5/radius];
>>>>>>
>>>>>> X and Y are the coordinates.
>>>>>>
>>>>>
>>>>
