Hi clever people

I'm trying to do something which I thought would be easy.
Read a file in, and for every row, create a array.

I want to be able to name the rows, as they are built.
So when row 1 is read in I get
int[] bob_1 = new int[0];
when the second row is read in, I get
int[] bob_2 = new int[0];

So at the end of running my program I effectively want bob_1, bob_2 and bob_3.
And then I can do something more interesting with them ...

I realise this is now slightly beyond my if-then-else capabilities, and was wondering if I could get some direction.

Thanks
B


The contents of /home/bob/test.csv
-1, -1, 1, -1, -1
-1, 1, 1, 1, -1
1, -1, -1, 1, -1

My Program
#!/usr/bin/rdmd
import std.stdio;
import std.array;
import std.conv;
import std.string;

void main()
{
  string inputFile = "/home/bob/test.csv";
//  string inputFile = "-1, -1, 1, -1, -1\n-1, 1, 1, 1, -1\n1, -1, -1, 1, -1\r\n";
  auto readInFile = File(inputFile);
  int count = 0;
  foreach(line; readInFile.byLine())
  {
    int[] bob = new int[0];
// int[] bob_NUMBER_ME = new int[0];
    foreach(item;line.split(","))
    {
      writeln(strip(item));
      bob ~=  to!int(strip(item));
    }
    writeln(bob);
    writefln("Line number %d", count);
    count++;
  }
  writeln("Done");
}

You should look into associative arrays ( http://dlang.org/hash-map .)

Example:

import std.stdio;

void main()
{
	int[][string] mybobs;
	mybobs["bob_1"] = [-1, -1, 1, -1, -1];
	mybobs["bob_2"] = [-1, 1, 1, 1, -1];
	mybobs["bob_3"] = [-1, 1, 1, 1, -1];
	writeln(mybobs);
}

On Tuesday, 13 May 2014 at 03:54:33 UTC, safety0ff wrote:
> You should look into associative arrays ( http://dlang.org/hash-map .)
>
> Example:
>
> import std.stdio;
>
> void main()
> {
> 	int[][string] mybobs;
> 	mybobs["bob_1"] = [-1, -1, 1, -1, -1];
> 	mybobs["bob_2"] = [-1, 1, 1, 1, -1];
> 	mybobs["bob_3"] = [-1, 1, 1, 1, -1];
> 	writeln(mybobs);
> }

Thanks for the quick reply, I'll look into that.

My issue is (which I didn't explain clearly, sorry) how do I do it with an unknown number of lines?
So my example has 3 lines. What if it had 300? or 3000?
Basically so I can run the same piece of code for any size file, and it will create a new named array for each line.
So I assume(?) I have to do something that will "name" each of these arrays at runtime.

So,
for(x;1 ... n)
  bob_x = ...

On 05/12/2014 08:47 PM, InfinityPlusB wrote:

> I want to be able to name the rows, as they are built.

First, no, you cannot name variables at run time because variables are concepts of source code; they don't exist in the compiled program.

> So when row 1 is read in I get
> int[] bob_1 = new int[0];
> when the second row is read in, I get
> int[] bob_2 = new int[0];

Well, it looks like a bob array. :) How about "naming" those rows as bob[0], bob[1], etc.

> So at the end of running my program I effectively want bob_1, bob_2 and
> bob_3.

Would zero-indexing work?

> And then I can do something more interesting with them ...
>
> I realise this is now slightly beyond my if-then-else capabilities, and
> was wondering if I could get some direction.

I had used the same naming scheme as a segway to my arrays chapter:

  http://ddili.org/ders/d.en/arrays.html

> The contents of /home/bob/test.csv
> -1, -1, 1, -1, -1
> -1, 1, 1, 1, -1
> 1, -1, -1, 1, -1
>
> My Program
> #!/usr/bin/rdmd
> import std.stdio;
> import std.array;
> import std.conv;
> import std.string;
>
> void main()
> {
>    string inputFile = "/home/bob/test.csv";
> //  string inputFile = "-1, -1, 1, -1, -1\n-1, 1, 1, 1, -1\n1, -1, -1,
> 1, -1\r\n";
>    auto readInFile = File(inputFile);
>    int count = 0;
>    foreach(line; readInFile.byLine())
>    {
>      int[] bob = new int[0];
> // int[] bob_NUMBER_ME = new int[0];
>      foreach(item;line.split(","))
>      {
>        writeln(strip(item));
>        bob ~=  to!int(strip(item));
>      }
>      writeln(bob);
>      writefln("Line number %d", count);
>      count++;
>    }
>    writeln("Done");
> }

Here is the inner loop with minimal changes to your program:

   int[][] bob;                        // <== Array of arrays

   foreach(line; readInFile.byLine())
   {
       int[] row;                      // <== Make a new row

       foreach(item;line.split(","))
       {
           writeln(strip(item));
           row ~= to!int(strip(item));
       }

       bob ~= row;                     // <== Add the row

     writefln("Line number %d", count);
     count++;
   }
   writeln(bob);

Ali

On Tuesday, 13 May 2014 at 04:26:04 UTC, Ali Çehreli wrote:
> On 05/12/2014 08:47 PM, InfinityPlusB wrote:
>
> > I want to be able to name the rows, as they are built.
>
> First, no, you cannot name variables at run time because variables are concepts of source code; they don't exist in the compiled program.

That's good to know, I'll stop trying to make that happen. :P

> Here is the inner loop with minimal changes to your program:
>
>    int[][] bob;                        // <== Array of arrays
>
>    foreach(line; readInFile.byLine())
>    {
>        int[] row;                      // <== Make a new row

yup, that will work.
If I wasn't hell bent on naming variables, I probably would have figured this out. :P

Thanks.

On 13/05/14 06:32, InfinityPlusB wrote:

> yup, that will work.
> If I wasn't hell bent on naming variables, I probably would have figured
> this out. :P

Perhaps you could use an associative array. Then you get sort of named variables.

-- 
/Jacob Carlborg