Parsing text in Julia- Invalid ascii sequence - file

Question

I'm trying to format a data file so that my other program will properly handle it. I am trying to handle the following data and I am getting a very weird error that I can't seem to put my finger on.
https://snap.stanford.edu/data/wiki-RfA.html
I am trying to format the data as [SRC TGT VOT], so I'd like the first two lines of my output file to be
1 2 1
3 2 1
because user 1 (stored in dictionary of users first) votes for user 2 with VOT 1 and then user 3 votes for user 2 with VOT 1. My problem is that when I try to run my code below, I always end up getting a very strange "invalid ascii sequence" error- can anyone help me identify the issue or perhaps find a way around this? It'd obviously be best if I could learn what I am doing wrong. Thank you!
Note, I understand that this is a bit specific of a question and I appreciate any help- I'm sort of baffled by this error and don't know how to resolve it at the moment.
f=open("original_vote_data.txt") #this is the file linked above
arr=readlines(f)
i=edge_count=src=tgt=vot=1
dict=Dict{ASCIIString, Int64}()
edges=["" for k=1:198275]
while i<1586200
src_temp=(arr[i])[5:end-2]
if (haskey(dict, src_temp))
new_src= dict[src_temp]
else
dict[src_temp]=src
new_src=src
src=src+1
end
tgt_temp=(arr[i+1])[5:end-2]
if (haskey(dict, tgt_temp))
new_tgt= dict[tgt_temp]
else
dict[tgt_temp]=tgt
new_tgt=tgt
tgt=tgt+1
end
vot_temp=(arr[i+2])[5]
edges[edge_count]=string(new_src)* " " * string(new_tgt)* " " *string(vot_temp)
edge_count=edge_count+1
i=i+8
end

Answer 1

Here we go - I'll write up my comment as an answer since it seems to have solved the question.
My hunch that the error stemmed from the fourth line (dict=Dict{ASCIIString, Int64}) was based on the fact that ASCIIStrings will error if you try to store non-ASCII characters in them. Since this file is coming from an international site, it's not unlikely that there are users with unicode characters in their names (or elsewhere in the data). So the simple fix is to change all instances of ASCIIString to UTF8String.
Just to make this answer a bit more complete, I downloaded the file and tried running the program. The simplest way to debug this is to run the script at top-level in the REPL and then inspect the program state after the error. After the error is thrown, i==3017. Now just try running each line of the while loop incrementally. You'll quickly see that line 3017 contains "SRC:Guðsþegn\n" — unicode, as I suspected. When you try to create a new entry in dict with that as the key, the error should have a backtrace to setindex! in dict.jl, where you'll see that it's trying to convert the key (a UTF8String) to an ASCIIString. So changing the dictionary type to have UTF8String keys solves the problem.
As it turns out, the edges array only contains strings of three integers (or sometimes a hyphen), so the ASCIIString there is ok, but still a little dangerous. I'd probably store that information in a more dedicated array of ints instead of converting it to a space-separated string: you know the first two elements in the string are ints, but the last element is unvalidated text from the file itself… which may be unicode or a space itself (which could mess up processing down the line).