So if I have an array of Bool, isprime (obtained by sieving, e.g.) of
length n, [1:n][isprime] will give the same result as primes(n)? That's
nice to know, though I'd call the syntax... interesting. :D
Concerning the original problem:
When we use do notation, an additional line x,y=p won't cost
You could also split that into multiple lines if readability is your goal:
~~~
sum(map(first,filter(x-x[1]!=x[2] x[2]=n
d[x[2]]==x[1],enumerate(d
~~~
becomes:
~~~
filtered = filter(enumerate(d)) do x
x[1]!=x[2] x[2]=n d[x[2]]==x[1] #expand to readability as desired
end
final =
There's also an open issue about splitting or splatting of tuples
within function arguments that's very relevant here: Allow tuple
destructuring in formal arguments,
https://github.com/JuliaLang/julia/issues/6614
It's a common use case that I run into often, especially with enumerate and
You could also use a list comprehension without enumerate:
d=[6,5,4,3,2,1,0]
n=4
sum(d[ Bool[i=n d[i]!=i d[d[i]]==i for i in 1:length(d)] ] )
18
Coming from numpy, I find this syntax intuitive, aside from the requirement
to explicitly set the comprehension type to Bool.
On Thursday, June
Nice! Just a note that the Bool[...] annotation is only required when
evaluating this in the REPL. Within a function definition the type of the
comprehension is correctly inferred.
On Thursday, June 19, 2014 9:25:40 AM UTC-7, Keith Campbell wrote:
You could also use a list comprehension
How about
pairs = [e for e in enumerate(sqr)]
filter(p - +(p...)%4 != 0, pairs)
?
--Peter
On Wednesday, June 18, 2014 3:34:24 PM UTC-7, gentlebeldin wrote:
When you come across Julia, and know (a bit of) Haskell, comparisons are
inevitable. Haskell has only functions with one argument,
See here (https://github.com/JuliaLang/julia/issues/554) for discussion on
currying in Julia.
On Wednesday, June 18, 2014 6:01:38 PM UTC-5, Peter Simon wrote:
How about
pairs = [e for e in enumerate(sqr)]
filter(p - +(p...)%4 != 0, pairs)
?
--Peter
On Wednesday, June 18, 2014 3:34:24
