Array index question

[Pjotr Wedersteers]

I have source information in a file, and (part of) this information comes as
coordinates.
A coordinate consists of a letter followed by a number, ranging from a1 to
i9
I'd like to count the number of occurrences of each coordinate, and put them
in a matrix.
The matrix should look like this (metasyntax):

matrix = array ['a'..'i'][1..9]

Later on in the script I'd like to be able to refer to a cell in the matrix
by using the same letter/number combo.
I know I can define an array using strings as keys, but how can I define
a..i as keys without the need to specify them all individually?
TIA
Pjotr

[Michael Fesser]

Re: Array index question

.oO(Pjotr Wedersteers)
[color=blue]
>I have source information in a file, and (part of) this information comes as
>coordinates.
>A coordinate consists of a letter followed by a number, ranging from a1 to
>i9
>I'd like to count the number of occurrences of each coordinate, and put them
>in a matrix.
>The matrix should look like this (metasyntax):
>
>matrix = array ['a'..'i'][1..9]
>
>Later on in the script I'd like to be able to refer to a cell in the matrix
>by using the same letter/number combo.
>I know I can define an array using strings as keys, but how can I define
>a..i as keys without the need to specify them all individually?[/color]

For example in a loop. This creates the empty matrix:

$matrix = array();
for ($i = ord('a'); $i <= ord('i'); $i++) {
$matrix[chr($i)] = array_fill(1, 9, 0);
}

or

$matrix = array();
foreach (range('a', 'i') as $i) {
$matrix[$i] = array_fill(1, 9, 0);
}

Then you can access the elements like this:

$coord = 'i9';
$matrix[$coord{0}][$coord{1}]++;


HTH
Micha

[steve]

Re: Array index question

"Pjotr Wedersteers" wrote:[color=blue]
> I have source information in a file, and (part of) this information
> comes as
> coordinates.
> A coordinate consists of a letter followed by a number, ranging[/color]
from[color=blue]
> a1 to
> i9
> I’d like to count the number of occurrences of each coordinate,
> and put them
> in a matrix.
> The matrix should look like this (metasyntax):
>
> matrix = array [’a’..’i’][1..9]
>
> Later on in the script I’d like to be able to refer to a cell in
> the matrix
> by using the same letter/number combo.
> I know I can define an array using strings as keys, but how can I
> define
> a..i as keys without the need to specify them all individually?
> TIA
> Pjotr[/color]

Hope this helps.

Read the coordinates from the file. I assume after you read then, they
are going to be in an array called $coor, where $coord would have
values like ’a1’ , ’b5’, etc.

Then do this:
foreach ($coord as $line) {
$alpha = preg_replace("/\d/", ’’, $line); //leaves only the
alpha part
$num = preg_replace("/\D/", ’’, $line); //leaves the numeric
part only
$newcoord[$alpha][$num] += 1; //increment count

}

You now have the counts for each coordinate combination.

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[Pjotr Wedersteers]

Re: Array index question

steve wrote:[color=blue]
> "Pjotr Wedersteers" wrote:[color=green]
> > I have source information in a file, and (part of) this information
> > comes as
> > coordinates.
> > A coordinate consists of a letter followed by a number, ranging[/color]
> from[color=green]
> > a1 to
> > i9
> > I'd like to count the number of occurrences of each coordinate,
> > and put them
> > in a matrix.
> > The matrix should look like this (metasyntax):
> >
> > matrix = array ['a'..'i'][1..9]
> >
> > Later on in the script I'd like to be able to refer to a cell in
> > the matrix
> > by using the same letter/number combo.
> > I know I can define an array using strings as keys, but how can I
> > define
> > a..i as keys without the need to specify them all individually?
> > TIA
> > Pjotr[/color]
>
> Hope this helps.
>
> Read the coordinates from the file. I assume after you read then, they
> are going to be in an array called $coor, where $coord would have
> values like 'a1' , 'b5', etc.
>
> Then do this:
> foreach ($coord as $line) {
> $alpha = preg_replace("/\d/", '', $line); //leaves only the
> alpha part
> $num = preg_replace("/\D/", '', $line); //leaves the numeric
> part only
> $newcoord[$alpha][$num] += 1; //increment count
>
> }
>
> You now have the counts for each coordinate combination.[/color]

Now that's a neat solution. Elegant too! Thanks a lot! Good thinking.
Pjotr

[Pjotr Wedersteers]

Re: Array index question

Michael Fesser wrote:[color=blue]
> .oO(Pjotr Wedersteers)
>[color=green]
>> I have source information in a file, and (part of) this information
>> comes as coordinates.
>> A coordinate consists of a letter followed by a number, ranging from
>> a1 to i9
>> I'd like to count the number of occurrences of each coordinate, and
>> put them in a matrix.
>> The matrix should look like this (metasyntax):
>>
>> matrix = array ['a'..'i'][1..9]
>>
>> Later on in the script I'd like to be able to refer to a cell in the
>> matrix by using the same letter/number combo.
>> I know I can define an array using strings as keys, but how can I
>> define a..i as keys without the need to specify them all
>> individually?[/color]
>
> For example in a loop. This creates the empty matrix:
>
> $matrix = array();
> for ($i = ord('a'); $i <= ord('i'); $i++) {
> $matrix[chr($i)] = array_fill(1, 9, 0);
> }
>
> or
>
> $matrix = array();
> foreach (range('a', 'i') as $i) {
> $matrix[$i] = array_fill(1, 9, 0);
> }
>
> Then you can access the elements like this:
>
> $coord = 'i9';
> $matrix[$coord{0}][$coord{1}]++;
>
>
> HTH
> Micha[/color]

Okay, thanks Micha. This will work. The range solution seems best suited for
me here. !
Pjotr