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D - Associative arrays and foreach.

reply "Julio C駸ar Carrascal Urquijo" <adnoctum phreaker.net> writes:
Didn't try the new foreach statement until today. Works great with normal
arrays but I don't know how to iterate over an associative array and obtain
"key" and "value" pairs for each item.

I think it should be something along the lines of:

void main()
{
    char[][char[]] hash;
    hash["en"] = "Hello, world!";
    hash["es"] = "。Hola, mundo!";

    foreach (char[] key: char[] value; hash)
    {
        printf("- %.*s\n", value);
    }
}

But the compiler doesn't support it. The thing is that "Hashtable" objects
will be forced to provide two overloaded "apply" functions:


template MyArray(T)
{
    struct Hashtable
    {
        operator apply(int delegate(T value) dg);
        operator apply(int delegate(char[] key, T value) dg);
    }
}

Wich probably will collide with what was discussed in the "Multiple
parameter foreach" thread.
Sep 12 2003
next sibling parent "Carlos Santander B." <carlos8294 msn.com> writes:
"Julio C駸ar Carrascal Urquijo" <adnoctum phreaker.net> wrote in message
news:bjtja5$1q5n$1 digitaldaemon.com...
| Didn't try the new foreach statement until today. Works great with normal
| arrays but I don't know how to iterate over an associative array and
obtain
| "key" and "value" pairs for each item.
|
| I think it should be something along the lines of:
|
| void main()
| {
|     char[][char[]] hash;
|     hash["en"] = "Hello, world!";
|     hash["es"] = "。Hola, mundo!";
|
|     foreach (char[] key: char[] value; hash)
|     {
|         printf("- %.*s\n", value);
|     }
| }
|

This is what I've done:

foreach ( char [] key; hash.keys )
    printf("%.*s\n",hash[key]);

It isn't pretty, but it works.

覧覧覧覧覧覧覧覧覧覧覧覧
Carlos Santander


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Sep 12 2003
prev sibling parent reply "Walter" <walter digitalmars.com> writes:
"Julio C駸ar Carrascal Urquijo" <adnoctum phreaker.net> wrote in message
news:bjtja5$1q5n$1 digitaldaemon.com...
 Didn't try the new foreach statement until today. Works great with normal
 arrays but I don't know how to iterate over an associative array and

 "key" and "value" pairs for each item.

 I think it should be something along the lines of:

 void main()
 {
     char[][char[]] hash;
     hash["en"] = "Hello, world!";
     hash["es"] = "。Hola, mundo!";

     foreach (char[] key: char[] value; hash)
     {
         printf("- %.*s\n", value);
     }
 }

I think I'll be adding that to foreach. But I am glad that foreach is turning out to be pretty popular!
Sep 12 2003
parent "Julio C駸ar Carrascal Urquijo" <adnoctum phreaker.net> writes:
 I think I'll be adding that to foreach. But I am glad that foreach is
 turning out to be pretty popular!

Yes, specially for those of us with a scripting background. I work every day with PHP and Python (the "for" in Python is really a "foreach") and this construct is basic for "everything" that you need to do.
Sep 13 2003