Re: naming a variable at runtime

[Jacob Carlborg via Digitalmars-d-learn]

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

Re: naming a variable at runtime

[safety0ff via Digitalmars-d-learn]

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);
}

Re: naming a variable at runtime

[InfinityPlusB via Digitalmars-d-learn]

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 = ...

Re: naming a variable at runtime

[Ali Çehreli via Digitalmars-d-learn]

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

Re: naming a variable at runtime

[InfinityPlusB via Digitalmars-d-learn]

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.