Or, redefine the question :> If you are not tied to string processing, reading the test_file as a string (if it is) and then splitting the string ```julia rowstrings = map(String, split(test_file, '\n')) # need the map to avoid SubString results, if it matters # then split the rows on ';' and convert to ?Float64 with NaN for error or ?Nullable Ints # and put the values in a matrix, processing the matrix you have the rows and cols ```
On Thursday, November 3, 2016 at 4:34:53 AM UTC-4, Tamas Papp wrote: > > Jeffrey, > > Thanks, but my question was about how to have line and column in the > error message. So I would like to have an error message like this: > > ERROR: Failed to parse "error" as type Int64 in column 2, line 3. > > My best idea so far: catch the error at each level, and add i and line > number. But this requires two try-catch-end blocks with rethrow. > > Extremely convoluted mess with rethrow here: > https://gist.github.com/tpapp/6f67ff36a228f47a1792e011d9b0fc13 > > It does what I want, but it is ugly. A simpler solution would be > appreciated. I am sure I am missing something. > > Best, > > Tamas > > On Thu, Nov 03 2016, Jeffrey Sarnoff wrote: > > > Tamas, > > > > running this > > > > > > > > typealias AkoString Union{String, SubString{String}} > > > > function parsefield{T <: Real, S <: AkoString}(::Type{T}, str::S) > > result = T(0) > > try > > result = parse(T, str) > > catch ArgumentError > > errormsg = string("Failed to parse \"",str,"\" as type ", T) > > throw(ErrorException(errormsg)) > > end > > return result > > end > > > > function parserow(schema, strings) > > # keep i for reporting column, currently not used > > [parsefield(T, string) for (i, (T, string)) in enumerate(zip(schema, > > strings))] > > end > > > > function parsefile(io, schema) > > line = 1 > > while !eof(io) > > strings = split(chomp(readline(io)), ';') > > parserow(schema, strings) > > line += 1 # currently not used, use for error reporting > > end > > end > > > > test_file = """ > > 1;2;3 > > 4;5;6 > > 7;8;error > > """ > > > > parsefile(IOBuffer(test_file), fill(Int, 3)) > > > > > > > > > > by evaluating parsefile(...), results in > > > > > > > > julia> parsefile(IOBuffer(test_file), fill(Int, 3)) > > ERROR: Failed to parse "error" as type Int64 > > in parsefield(::Type{Int64}, ::SubString{String}) at ./REPL[2]:7 > > in (::##1#2)(::Tuple{Int64,Tuple{DataType,SubString{String}}}) at > > ./<missing>:0 > > in collect_to!(::Array{Int64,1}, > > > ::Base.Generator{Enumerate{Base.Zip2{Array{DataType,1},Array{SubString{String},1}}},##1#2}, > > > > ::Int64, ::Tuple{Int64,Tuple{Int64,Int64}}) at ./array.jl:340 > > in > > > collect(::Base.Generator{Enumerate{Base.Zip2{Array{DataType,1},Array{SubString{String},1}}},##1#2}) > > > > at ./array.jl:308 > > in parsefile(::Base.AbstractIOBuffer{Array{UInt8,1}}, > ::Array{DataType,1}) > > at ./REPL[4]:5 > > > > > > > > > > > > On Wednesday, November 2, 2016 at 1:01:30 PM UTC-4, Tamas Papp wrote: > >> > >> This is a conceptual question. Consider the following (extremely > >> stylized, but self-contained) code > >> > >> parsefield{T <: Real}(::Type{T}, string) = parse(T, string) > >> > >> function parserow(schema, strings) > >> # keep i for reporting column, currently not used > >> [parsefield(T, string) for (i, (T, string)) in > enumerate(zip(schema, > >> strings))] > >> end > >> > >> function parsefile(io, schema) > >> line = 1 > >> while !eof(io) > >> strings = split(chomp(readline(io)), ';') > >> parserow(schema, strings) > >> line += 1 # currently not used, use for error reporting > >> end > >> end > >> > >> test_file = """ > >> 1;2;3 > >> 4;5;6 > >> 7;8;error > >> """ > >> > >> parsefile(IOBuffer(test_file), fill(Int, 3)) > >> > >> This will fail with an error message > >> > >> ERROR: ArgumentError: invalid base 10 digit 'e' in "error" > >> in tryparse_internal(::Type{Int64}, ::SubString{String}, ::Int64, > >> ::Int64, ::Int64 > >> , ::Bool) at ./parse.jl:88 > >> in parse(::Type{Int64}, ::SubString{String}) at ./parse.jl:152 > >> in parsefield(::Type{Int64}, ::SubString{String}) at ./REPL[152]:1 > >> in (::##5#6)(::Tuple{Int64,Tuple{DataType,SubString{String}}}) at > >> ./<missing>:0 > >> in collect_to!(::Array{Int64,1}, > >> ::Base.Generator{Enumerate{Base.Zip2{Array{DataTy > >> pe,1},Array{SubString{String},1}}},##5#6}, ::Int64, > >> ::Tuple{Int64,Tuple{Int64,Int64 > >> }}) at ./array.jl:340 > >> in > >> > collect(::Base.Generator{Enumerate{Base.Zip2{Array{DataType,1},Array{SubString{ > > > >> > >> String},1}}},##5#6}) at ./array.jl:308 > >> in parsefile(::Base.AbstractIOBuffer{Array{UInt8,1}}, > >> ::Array{DataType,1}) at ./RE > >> PL[154]:5 > >> > >> Instead, I would like to report something like this: > >> > >> ERROR: Failed to parse "error" as Int on line 3, column 3. > >> > >> What's the idiomatic way of doing this in Julia? My problem is that > >> parsefield fails without knowing line or column (i in parserow). I > could > >> catch and rethrow, constructing an error object gradually. Or I could > >> pass line and column numbers to parserow and parsefield for error > >> reporting, but that seems somehow inelegant (I have seen it in code > >> though). > >> > >> Best, > >> > >> Tamas > >> >
