does `copy` work? although `bytestring` also seems like a good method for this also. it seems wrong to me also that `match` is making a copy of the original string (if that is indeed what it is doing)
On Tue, Jul 21, 2015 at 6:57 PM andrew cooke <and...@acooke.org> wrote: > > string(bytestring(...)) seems to do it. would appreciate any more > efficient solutions (and confirmation the analysis is correct - is this > worth filing as an issue?) > > > On Tuesday, 21 July 2015 19:33:05 UTC-3, andrew cooke wrote: >> >> >> well, this was fun... the following code rapidly triggers the OOM killer >> on my machine (julia 0.4 trunk): >> >> s = repeat("a", 1000000) >> l = Any[] >> r = r"^\w" >> >> for i in 1:length(s) >> m = match(r, s[i:end]) >> push!(l, m.match) >> end >> >> note that: (1) the regexp is only matching one character, so the array l >> is at most a million characters long. >> >> what i think is happening (but this is only a guess) is that s[i:end] is >> being passed though to the c level regexp library as a new string. the >> result (m.match) is then a substring into that. because the substring is >> kept around, the backing string cannot be collected. and so there's an n^2 >> memory use. >> >> ideally, i don't think a new copy of the string should be passed to the >> regexp engine. maybe i am wrong? >> >> anyway, for now, if the above is right, i need some way to copy m.match. >> as far as i can tell string() doesn't help. so what works? or am i wrong? >> >> thanks, >> andrew >> >