I was expecting the following to read a file into an N x M array of characters: load(file) = [c for l in eachline(file), c in l] where the file’s contents are: MMMSXXMASM MSAMXMSMSA AMXSXMAAMM MSAMASMSMX XMASAMXAMM XXAMMXXAMA SMSMSASXSS SAXAMASAAA MAMMMXMMMM MXMXAXMASX However, it seems to retur…

Only solution I’ve found so far (short of an explicit nested loop) is this: load(file) = reduce(vcat, permutedims(collect(l)) for l in eachline(file)) which is rather ugly, but does produce the desired result: julia> load("/tmp/example.txt") 10×10 Matrix{Char}: 'M' 'M' 'M' 'S' 'X' 'X' 'M' …

The nested iteration does not allow for depend loops. I believe the rationale behind that is that the nested iteration yields an rectangular Array which is not guaranteed if the loops’ lengths can depend on each other. Here are some other suggestions: eachline(file) |> stack |> permutedims permute…

Depending on what output you want, you can do: load(file) = [c for l in eachline(file) for c in l] and reshape the vector to a matrix.

If you want to save time and the file is formatted cleanly as in the question, using mmap will probably be fastest. Also note the use of UInt8 instead of Char, as Char is really a 32-bit Unicode point, but UInt8 is appropriate for old style ASCII only files. julia> using Mmap julia> f = open("/tmp…

Oh cool, it’s good to know how easy it is to mmap files when they’re in clean formats like this. FWIW this is coming from this year’s advent of code challenge, day 4 .

[image] How to use `readdlm` to read in a Matrix{Char} General Usage Sometimes it’s useful to read in the file as a matrix of characters, in other words, split on empty char – but currently, readdlm(path, dlm::Char) the second argument has to be a Char and there’s no empty…

here another reference to the AOC 2024 context/contest. Refer to the ZULIP blog. I would have liked to see the discussions about AOC problems here instead. I tried my hand at the problem of day 4, I had a lot of difficulty even simply activating the spoiler of my proposed solutions.

Nested iteration in comprehension

General Usage

jling December 5, 2024, 6:53am 8

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Nested iteration in comprehension

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