Maybe... I really don't like the %% syntax, though - it's so cluttered. I agree it makes sense, and maybe one can get used to it, but it does use a lot of "ink". But I have no better suggestions :)
// T On Monday, April 28, 2014 5:58:47 PM UTC+2, Stefan Karpinski wrote: > > I wonder if this is important enough to warrant an operator. Something > like v[i%%n]? > > > On Mon, Apr 28, 2014 at 6:53 AM, Tim Holy <[email protected] <javascript:> > > wrote: > >> There's mod1, if that helps. >> >> --Tim >> >> On Monday, April 28, 2014 02:57:09 AM Tomas Lycken wrote: >> > In languages with zero-indexed vectors, I can easily let my indices >> "wrap" >> > by taking a modulus: >> > >> > N = length(v) >> > for i = 0:N-1 >> > v[i+1 % N] = ... >> > end >> > >> > will loop from the second element to the last, and then take the first, >> > since N % N == 0. However, with Julia's 1-indexed arrays, it's not that >> > easy - at some point, I'll end up at index 0: >> > >> > N = length(v) >> > for i = 1:N >> > v[i + 1 % N] = ... # breaks at i = N-1, since index then becomes 0 >> > end >> > >> > I could first offset my entire loop index by one, take the modulus, and >> > then add one again: >> > >> > N = length(v) >> > for i = 0:N-1 >> > v[(i+1 % N) + 1] = ... >> > end >> > >> > but this seems clunky to me, and is difficult to understand at first >> glance >> > (maybe not to current me, but to me-in-a-month trying to figure out what >> > this code does...). Is there a more idiomatic way to do the same thing >> in >> > Julia? >> > >> > My actual problem is having a (sorted) list of vertices in a polygon, >> and >> > wanting to loop over the edges (i.e. adjacent pairs in the list), so in >> > each step I want to access something like v[i+1]-v[i] and have the >> > end-points close the loop. >> > >> > Thanks in advance, >> > >> > // T >> > >
