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digitalmars.D.learn - string-int[] array

reply "Dennis Ritchie" <dennis.ritchie mail.ru> writes:
Is it possible to create such an array in which you can store 
strings and numbers at the same time?

string-int[] array = [4, "five"];
Mar 08 2015
next sibling parent reply "Baz" <bb.temp gmx.com> writes:
On Sunday, 8 March 2015 at 18:05:33 UTC, Dennis Ritchie wrote:

 Is it possible to create such an array in which you can store 
 strings and numbers at the same time?

 string-int[] array = [4, "five"];


using an array of tuple it works:

----
import std.stdio;
import std.typecons;

alias T = Tuple!(string, int);

void main(string[] args)
{
     T[] tarr;
     tarr ~= T("a",65);
     tarr ~= T("b",66);
     writeln(tarr);
}
----


 [Tuple!(string, int)("a", 65), Tuple!(string, int)("b", 66)]
Mar 08 2015
next sibling parent reply "Baz" <bb.temp gmx.com> writes:
On Sunday, 8 March 2015 at 18:18:15 UTC, Baz wrote:

 On Sunday, 8 March 2015 at 18:05:33 UTC, Dennis Ritchie wrote:

 Is it possible to create such an array in which you can store 
 strings and numbers at the same time?

 string-int[] array = [4, "five"];


 using an array of tuple it works:

 ----
 import std.stdio;
 import std.typecons;

 alias T = Tuple!(string, int);

 void main(string[] args)
 {
     T[] tarr;
     tarr ~= T("a",65);
     tarr ~= T("b",66);
     writeln(tarr);
 }
 ----


 [Tuple!(string, int)("a", 65), Tuple!(string, int)("b", 66)]




mmmh maybe off-topic, you probably don't what pairs but either a 
string representing an int or an int, do you ?
If so then an array of union ?
Mar 08 2015
parent "Dennis Ritchie" <dennis.ritchie mail.ru> writes:
On Sunday, 8 March 2015 at 18:38:02 UTC, Dennis Ritchie wrote:

 Thanks, will do.


No, will not work.

On Sunday, 8 March 2015 at 18:25:33 UTC, Baz wrote:

 mmmh maybe off-topic, you probably don't what pairs but either 
 a string representing an int or an int, do you ?
 If so then an array of union ?


string-int[] array;
a = [5, "v", 4, "t", "a", "b", 7, 9, 10, 15, "example"];
writeln(a);	// [5, "v", 4, "t", "a", "b", 7, 9, 10, 15, "example"]
Mar 08 2015
prev sibling parent reply "Dennis Ritchie" <dennis.ritchie mail.ru> writes:
On Sunday, 8 March 2015 at 18:18:15 UTC, Baz wrote:

 import std.stdio;
 import std.typecons;

 alias T = Tuple!(string, int);

 void main(string[] args)
 {
     T[] tarr;
     tarr ~= T("a",65);
     tarr ~= T("b",66);
     writeln(tarr);
 }
 ----


 [Tuple!(string, int)("a", 65), Tuple!(string, int)("b", 66)]




Thanks, will do.
Mar 08 2015
parent reply "Meta" <jared771 gmail.com> writes:
On Sunday, 8 March 2015 at 18:38:02 UTC, Dennis Ritchie wrote:

 On Sunday, 8 March 2015 at 18:18:15 UTC, Baz wrote:

 import std.stdio;
 import std.typecons;

 alias T = Tuple!(string, int);

 void main(string[] args)
 {
    T[] tarr;
    tarr ~= T("a",65);
    tarr ~= T("b",66);
    writeln(tarr);
 }
 ----


 [Tuple!(string, int)("a", 65), Tuple!(string, int)("b", 66)]




 Thanks, will do.


It might be better to use std.variant.Algebraic. An array of 
tuples is wasteful of memory as you only need one or the other.

import std.variant;

alias IntOrStr = Algebraic!(int, string);

IntOrStr[] makeIntOrStrArray(T...)(T vals)
{
	import std.algorithm;
	import std.array;
	
	auto result = new IntOrStr[](T.length);
	foreach (i, val; vals)
	{
		result[i] = IntOrStr(val);
	}
	
	return result;
}

void main()
{
	IntOrStr[] arr = makeIntOrStrArray(4, "five");
}
Mar 08 2015
parent "Baz" <bb.temp gmx.com> writes:
On Sunday, 8 March 2015 at 18:54:43 UTC, Meta wrote:

 On Sunday, 8 March 2015 at 18:38:02 UTC, Dennis Ritchie wrote:

 On Sunday, 8 March 2015 at 18:18:15 UTC, Baz wrote:

 import std.stdio;
 import std.typecons;

 alias T = Tuple!(string, int);

 void main(string[] args)
 {
   T[] tarr;
   tarr ~= T("a",65);
   tarr ~= T("b",66);
   writeln(tarr);
 }
 ----


 [Tuple!(string, int)("a", 65), Tuple!(string, int)("b", 66)]




 Thanks, will do.


 It might be better to use std.variant.Algebraic. An array of 
 tuples is wasteful of memory as you only need one or the other.

 import std.variant;

 alias IntOrStr = Algebraic!(int, string);

 IntOrStr[] makeIntOrStrArray(T...)(T vals)
 {
 	import std.algorithm;
 	import std.array;
 	
 	auto result = new IntOrStr[](T.length);
 	foreach (i, val; vals)
 	{
 		result[i] = IntOrStr(val);
 	}
 	
 	return result;
 }

 void main()
 {
 	IntOrStr[] arr = makeIntOrStrArray(4, "five");
 }


Yes, but the tuple is used here because i misunderstood the 
question, cf my own answer to my first answer, anyway, never mind.
Mar 08 2015
prev sibling next sibling parent reply "Kagamin" <spam here.lot> writes:
http://dpaste.dzfl.pl/2c8d4a7d9ef0 like this.
Mar 08 2015
next sibling parent "Dennis Ritchie" <dennis.ritchie mail.ru> writes:
On Sunday, 8 March 2015 at 18:54:43 UTC, Meta wrote:

 On Sunday, 8 March 2015 at 18:38:02 UTC, Dennis Ritchie wrote:

 On Sunday, 8 March 2015 at 18:18:15 UTC, Baz wrote:

 import std.stdio;
 import std.typecons;

 alias T = Tuple!(string, int);

 void main(string[] args)
 {
   T[] tarr;
   tarr ~= T("a",65);
   tarr ~= T("b",66);
   writeln(tarr);
 }
 ----


 [Tuple!(string, int)("a", 65), Tuple!(string, int)("b", 66)]




 Thanks, will do.


 It might be better to use std.variant.Algebraic. An array of 
 tuples is wasteful of memory as you only need one or the other.

 import std.variant;

 alias IntOrStr = Algebraic!(int, string);

 IntOrStr[] makeIntOrStrArray(T...)(T vals)
 {
 	import std.algorithm;
 	import std.array;
 	
 	auto result = new IntOrStr[](T.length);
 	foreach (i, val; vals)
 	{
 		result[i] = IntOrStr(val);
 	}
 	
 	return result;
 }

 void main()
 {
 	IntOrStr[] arr = makeIntOrStrArray(4, "five");
 }


Thanks.

On Sunday, 8 March 2015 at 18:57:38 UTC, Kagamin wrote:

 http://dpaste.dzfl.pl/2c8d4a7d9ef0 like this.
struct IntString
{
	string svalue;
	this(string s){ svalue=s; }
	this(int i){ ivalue=i; }
	int ivalue() const
	{
		assert(svalue.length==0);
		return cast(int)svalue.ptr;
	}
	void ivalue(int i)
	{
		svalue=cast(string)(cast(char*)0)[i..i];
	}
}

int main()
{
	auto s=IntString(5);
	assert(s.ivalue==5);
	s.ivalue=-6;
	assert(s.ivalue==-6);
	return 0;
}


Thanks.
Mar 08 2015
prev sibling next sibling parent reply "Meta" <jared771 gmail.com> writes:
On Sunday, 8 March 2015 at 18:57:38 UTC, Kagamin wrote:

 http://dpaste.dzfl.pl/2c8d4a7d9ef0 like this.


What in the world is that code doing? I'm having a hard time 
wrapping my head around this.
Mar 08 2015
parent reply FG <home fgda.pl> writes:
On 2015-03-08 at 20:26, Meta wrote:

 On Sunday, 8 March 2015 at 18:57:38 UTC, Kagamin wrote:

 http://dpaste.dzfl.pl/2c8d4a7d9ef0 like this.


 What in the world is that code doing? I'm having a hard time wrapping my head
around this.


It's a trick to reuse string internals to store an int.
A string is a struct with two values (length, ptr).
ivalue(i) is used to set ptr = i and length = 0.

Except that with this solution you will confuse empty strings with ints.
You could give such strings special treatment by replacing:

     this(string s){ svalue=s; }

with:

     this(string s){ svalue=s; if (!s.length) svalue =
cast(string)(cast(char*)0)[X..X]; }
     // where X is some magic int value to mark that we are dealing with an
empty string,

you'd still be confused if someone actually wanted to store the X value.
Mar 08 2015
next sibling parent "Meta" <jared771 gmail.com> writes:
On Sunday, 8 March 2015 at 21:41:44 UTC, FG wrote:

 On 2015-03-08 at 20:26, Meta wrote:

 On Sunday, 8 March 2015 at 18:57:38 UTC, Kagamin wrote:

 http://dpaste.dzfl.pl/2c8d4a7d9ef0 like this.


 What in the world is that code doing? I'm having a hard time 
 wrapping my head around this.


 It's a trick to reuse string internals to store an int.
 A string is a struct with two values (length, ptr).
 ivalue(i) is used to set ptr = i and length = 0.

 Except that with this solution you will confuse empty strings 
 with ints.
 You could give such strings special treatment by replacing:

     this(string s){ svalue=s; }

 with:

     this(string s){ svalue=s; if (!s.length) svalue = 
 cast(string)(cast(char*)0)[X..X]; }
     // where X is some magic int value to mark that we are 
 dealing with an empty string,

 you'd still be confused if someone actually wanted to store the 
 X value.


Oh, I see. What was tripping me up was

`svalue=cast(string)(cast(char*)0)[i..i];`

But I see now that it's just creating an empty string.
Mar 08 2015
prev sibling parent "Kagamin" <spam here.lot> writes:
On Sunday, 8 March 2015 at 21:41:44 UTC, FG wrote:

 Except that with this solution you will confuse empty strings 
 with ints.


The idea was to only make it memory-safe without union.
Mar 10 2015
prev sibling parent ketmar <ketmar ketmar.no-ip.org> writes:
On Sun, 08 Mar 2015 18:57:37 +0000, Kagamin wrote:


 http://dpaste.dzfl.pl/2c8d4a7d9ef0 like this.


i hate annoying beginners too, but not to SUCH extent.=
Mar 09 2015
prev sibling parent reply "Paul" <paul example.com> writes:
On Sunday, 8 March 2015 at 18:05:33 UTC, Dennis Ritchie wrote:

 Is it possible to create such an array in which you can store 
 strings and numbers at the same time?

 string-int[] array = [4, "five"];


As there's no mention of performance, what's wrong with a plain 
old string array with a bit of conversion and error checking?

string[] soup = ["4", "Test", "5", "More Test"];
Mar 08 2015
parent reply Max Klyga <max.klyga gmail.com> writes:
On 2015-03-08 21:11:42 +0000, Paul said:


 On Sunday, 8 March 2015 at 18:05:33 UTC, Dennis Ritchie wrote:

 Is it possible to create such an array in which you can store strings 
 and numbers at the same time?
 
 string-int[] array = [4, "five"];


 
 As there's no mention of performance, what's wrong with a plain old 
 string array with a bit of conversion and error checking?
 
 string[] soup = ["4", "Test", "5", "More Test"];




(or any ML-family language) and clumsy in C-family languages.

In language holy wars the only winning move is not to play.
Mar 08 2015
next sibling parent "Dennis Ritchie" <dennis.ritchie mail.ru> writes:
On Sunday, 8 March 2015 at 21:18:31 UTC, Max Klyga wrote:

 OP is fighting a loosing battle in flame war on some obscure 


 C-family languages.

 In language holy wars the only winning move is not to play.


I have not played in a Holy war.
Mar 08 2015
prev sibling parent "Paul" <paul example.com> writes:
On Sunday, 8 March 2015 at 21:18:31 UTC, Max Klyga wrote:

 On 2015-03-08 21:11:42 +0000, Paul said:


 On Sunday, 8 March 2015 at 18:05:33 UTC, Dennis Ritchie wrote:

 Is it possible to create such an array in which you can store 
 strings and numbers at the same time?
 
 string-int[] array = [4, "five"];


 
 As there's no mention of performance, what's wrong with a 
 plain old string array with a bit of conversion and error 
 checking?
 
 string[] soup = ["4", "Test", "5", "More Test"];


 OP is fighting a loosing battle in flame war on some obscure 


 C-family languages.

 In language holy wars the only winning move is not to play.


Yawn :D
Mar 08 2015