Is there a skip parameter in Julia's range?

Question

In Python, we could iterate using a for-loop and skip the indices using the skip parameter as such:

max_num, jump = 100, 10
for i in range(0, max_num, jump):
    print (i)

I could achieve the same with a while loop by doing this:

max_num, jump = 100, 10
i = 0
while i < max_num
    print(i)
    i+=jump
end

And using the same i+=jump syntax shown below in the for-loop doesn't skip the index:

for i in range(0,max_num)
    print(i)
    i+=jump
end

Within a for-loop is "skipping" possible? If so, how?

score 9 · Accepted Answer · answered Feb 07 '17 at 08:30

9

You can just do

max_num, step = 100, 10

for i in 0:step:max_num
    println(i)
end

Using range(), you do not specify max_num, but the desired number of iterations. So 0:step:max_num equals range(0, step, max_num/step).

answered Feb 07 '17 at 08:30

Toterich

ymonad · Answer 2 · 2017-02-07T08:35:49.740

3

The syntax is a little bit different in Julia.

for i in range(0, 3, 10)
   println(i)
end

[out]:

There's another syntax start:step:max_num see @Sayse 's answer for detali

edited Feb 07 '17 at 08:35

answered Feb 07 '17 at 08:23

ymonad

score 1 · Answer 3 · edited Feb 07 '17 at 08:30

1

You do it in your first snipppet (define it in the range). Aside from that you'd have to use a modulo

for i in range(0,max_num):
    if(i % jump != 0):
        continue
    print(i)

edited Feb 07 '17 at 08:30

Nat Gillin

answered Feb 07 '17 at 08:17

Sayse

Using modulus would be iterating through all `max_num` of cycles, checking the modulo at every iteration, right? – Nat Gillin Feb 07 '17 at 08:24
@NatGillin - Thats correct, its preferred to use the range – Sayse Feb 07 '17 at 08:25

score 1 · Answer 4 · answered Feb 07 '17 at 16:29

1

start:jump:end

Example:

a = 0:10:100

You can loop using that:

for a in 0:10:100
  println(a)
end

answered Feb 07 '17 at 16:29

Chris Rackauckas

4 Answers4