• IK (17/17) Jun 18 2012 I'm attempting Project Euler's problem 11.
• bearophile (17/18) Jun 18 2012 I don't know the cause of your problem. While investigating it I
• IK (12/12) Jun 18 2012 Hmm does your code generate a 1D `array` as a grid, bearophile?
• Timon Gehr (11/23) Jun 18 2012 IIRC formattedRead would require input similar to
• IK (31/31) Jun 19 2012 This program below fails if the file contains an empty line.
• IK (6/6) Jun 19 2012 Now I see! The error message is a bit awkward, it should show
• bearophile (4/6) Jun 19 2012 Hara knows. Maybe it's a bug.

IK <istvan.karolyi rocketmail.com> writes:

I'm attempting Project Euler's problem 11.
http://projecteuler.net/problem=11

Currently, my code looks like posted below, and it gives
    object.Error: Access Violation
at runtime.

Question: how to read that grid from a text file? (See link above.)
If you have ideas for using something other than uint[20][20], please say.
Thank you.

import std.stdio;
import std.stream;

void main()
{
	uint[20][20] grid;
	BufferedFile input_file;

	input_file.open("p011_input.txt");
	input_file.readf("%(%(%d %)\n%)", grid);
}

"bearophile" <bearophileHUGS lycos.com> writes:

IK:

 Question: how to read that grid from a text file?

I don't know the cause of your problem. While investigating it I 
have filed another bug:
http://d.puremagic.com/issues/show_bug.cgi?id=8260


In the meantime this (a bit scary) code solves your reading 
problem:

import std.stdio, std.algorithm, std.range, std.conv;

void main() {
     const grid = File("table.txt")
                  .byLine().map!(r => std.algorithm.splitter(r)
                                      .map!(to!int)()
                                      .array())()
                  .array();
     writeln(grid);
}


Bye,
bearophile

IK <istvan.karolyi rocketmail.com> writes:

Hmm does your code generate a 1D `array` as a grid, bearophile?
Anyway thanks, I'll compile it shortly.

My own code evolved to what's below and gives a Range violation.
Also I don't understand why formattedRead can't just accept a casted
`opSlice.dup`, is it a bug?

void main()
{
	uint[20][20] grid;
	auto input_file = new MmFile("p011_input.txt");
	string temp = cast(string)input_file.opSlice;

	formattedRead(temp, "%(%(%s %)\n%)", &grid);
}

Timon Gehr <timon.gehr gmx.ch> writes:

On 06/18/2012 05:11 PM, IK wrote:
 Hmm does your code generate a 1D `array` as a grid, bearophile?
 Anyway thanks, I'll compile it shortly.

 My own code evolved to what's below and gives a Range violation.
 Also I don't understand why formattedRead can't just accept a casted
 `opSlice.dup`, is it a bug?

Yes.

 void main()
 {
 	uint[20][20] grid;
 	auto input_file = new MmFile("p011_input.txt");
 	string temp = cast(string)input_file.opSlice;

 	formattedRead(temp, "%(%(%s %)\n%)",&grid);
 }

IIRC formattedRead would require input similar to

"[[1,2,3,4,5],[1,2,3,4,5],[1,2,3,4,5],[1,2,3,4,5],[1,2,3,4,5]]"

This works:

void main()
{
     auto input_file = new MmFile("p011_input.txt");
     auto text = cast(string)input_file[];
     auto grid = text.splitLines.map!(_=>_.split.to!(uint[])).array;
}

"IK" <istvan.karolyi rocketmail.com> writes:

This program below fails if the file contains an empty line.
Why exactly does this happen?
Does ln get a mangled value when a line is empty?


     import std.format;
     import std.stdio;

     void main()
     {
         int[] test;

         foreach (ln; File("ints.txt").byLine)
             formattedRead(ln, "%(%d %)", &test);

         writefln("%(%d %)", test);
     }


std.conv.ConvException c:\dmd2\windows\bin\..\..\src\phobos\std\conv.d(1779): 
Unexpected '
' when converting from type char[] to type int
----------------
4169C4
41684F
405E63
405BDF
405A06
405964
40573F
4055CE
40246B
4020CC
4083A0
4083DA
407FFB
41DB21
----------------

"IK" <istvan.karolyi rocketmail.com> writes:

Now I see! The error message is a bit awkward, it should show 
'\n' instead.
(It should also use Windows line endings on a Windows machine, 
but that's a minor point.)

So indeed formattedRead() fails for a newline. Can this be 
considered a bug?

"bearophile" <bearophileHUGS lycos.com> writes:

IK:

 So indeed formattedRead() fails for a newline. Can this be 
 considered a bug?

Hara knows. Maybe it's a bug.

Bye,
bearophile