• Namal (9/9) Oct 19 2015 Is it possible to create a foreach loop with a breakstetemen?
• Dominikus Dittes Scherkl (2/11) Oct 19 2015 Of course. D uses even the same keyword for this as C does: break.
• Daniel Kozak via Digitalmars-d-learn (13/25) Oct 19 2015 V Mon, 19 Oct 2015 14:28:03 +0000
• Rikki Cattermole (12/21) Oct 19 2015 If you want to break a specific loop, use labels.
• Namal (3/28) Oct 19 2015 Hey thanks, until now I just used bool variables as break flags.
• Namal (4/4) Oct 19 2015 Is it possible to use foreach backwards?
• novice2 (4/5) Oct 19 2015 yes
• Mike Parker (9/13) Oct 19 2015 foreach_reverse(i; 1 .. 20)
• Namal (4/4) Nov 03 2015 Hello guys,
• wobbles (5/9) Nov 03 2015 auto arr = ["Hello", "World"];
• Adam D. Ruppe (3/6) Nov 03 2015 for many of them it is as simple as:
• Namal (10/16) Nov 03 2015 Thank you. I am still struggling with the functional ways of D.
• wobbles (6/25) Nov 03 2015 writefln("Count is: %s", arr
• wobbles (3/30) Nov 03 2015 Oh, I realise now you were counting the number of 'false' values.
• Namal (7/36) Nov 03 2015 How do I save sum as integer or something I try;
• Namal (4/33) Nov 03 2015 well I tried this that way, but my count stays 0, same as if I do
• Edwin van Leeuwen (7/13) Nov 03 2015 Shouldn't you be using walkLength instead of sum, since you are
• wobbles (5/19) Nov 03 2015 That would work also yes.
• Edwin van Leeuwen (5/26) Nov 03 2015 false converts to zero, so
• TheFlyingFiddle (4/7) Nov 03 2015 You could also use count:
• ixid (11/12) Nov 04 2015 reduce!((x, y) => x + !y)(0, arr).writeln;

Namal <sotis22 mail.ru> writes:

Is it possible to create a foreach loop with a breakstetemen?

I mean something like that for the second loop where i want to 
break if element from:

int []  g = [9,15,21];
int [] v = [2,3,5,7,8,9,11,13,17,19];

foreach(j;1..10)
for(int i = 0; v[i]<j;++i){
  do something;
}

Dominikus Dittes Scherkl <Dominikus.Scherkl continental-corporation.com> writes:

On Monday, 19 October 2015 at 14:28:06 UTC, Namal wrote:
 Is it possible to create a foreach loop with a breakstetemen?

 I mean something like that for the second loop where i want to 
 break if element from:

 int []  g = [9,15,21];
 int [] v = [2,3,5,7,8,9,11,13,17,19];

 foreach(j;1..10)
 for(int i = 0; v[i]<j;++i){
  do something;
 }

Of course. D uses even the same keyword for this as C does: break.

Daniel Kozak via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> writes:

V Mon, 19 Oct 2015 14:28:03 +0000
Namal via Digitalmars-d-learn <digitalmars-d-learn puremagic.com>
napsáno:

 Is it possible to create a foreach loop with a breakstetemen?
 
 I mean something like that for the second loop where i want to 
 break if element from:
 
 int []  g = [9,15,21];
 int [] v = [2,3,5,7,8,9,11,13,17,19];
 
 foreach(j;1..10)
 for(int i = 0; v[i]<j;++i){
   do something;
 }

I am not sure what you exactly want, but you can break foreach
statement:

int []  g = [9,15,21];
int [] v = [2,3,5,7,8,9,11,13,17,19];

outerfor: foreach(j;1..10)
for(int i = 0; v[i]<j;++i){
  do something;
  if (iWantToBreak)
    break outerfor;
}

Rikki Cattermole <alphaglosined gmail.com> writes:

On 20/10/15 3:28 AM, Namal wrote:
 Is it possible to create a foreach loop with a breakstetemen?

 I mean something like that for the second loop where i want to break if
 element from:

 int []  g = [9,15,21];
 int [] v = [2,3,5,7,8,9,11,13,17,19];

 foreach(j;1..10)
 for(int i = 0; v[i]<j;++i){
   do something;
 }

If you want to break a specific loop, use labels.

L1:
	foreach(i; 0 .. 10) {
	
	L2:	foreach(j; 0 .. 10) {
			// break L1;

			// break L2;
			// or
			// break;
		}
	}

Namal <sotis22 mail.ru> writes:

On Monday, 19 October 2015 at 14:43:04 UTC, Rikki Cattermole 
wrote:
 On 20/10/15 3:28 AM, Namal wrote:
 Is it possible to create a foreach loop with a breakstetemen?

 I mean something like that for the second loop where i want to 
 break if
 element from:

 int []  g = [9,15,21];
 int [] v = [2,3,5,7,8,9,11,13,17,19];

 foreach(j;1..10)
 for(int i = 0; v[i]<j;++i){
   do something;
 }

 If you want to break a specific loop, use labels.

 L1:
 	foreach(i; 0 .. 10) {
 	
 	L2:	foreach(j; 0 .. 10) {
 			// break L1;

 			// break L2;
 			// or
 			// break;
 		}
 	}

Hey thanks, until now I just used bool variables as break flags.

Namal <sotis22 mail.ru> writes:

Is it possible to use foreach backwards?

foreach(int i;20..1)
  writeln(i);

compiles but I get nothing.

novice2 <sorry noem.ail> writes:

On Monday, 19 October 2015 at 15:56:00 UTC, Namal wrote:
 Is it possible to use foreach backwards?

yes
http://dlang.org/statement.html#ForeachStatement
http://dpaste.dzfl.pl/cf847a9e1595

Mike Parker <aldacron gmail.com> writes:

On Monday, 19 October 2015 at 15:56:00 UTC, Namal wrote:
 Is it possible to use foreach backwards?

 foreach(int i;20..1)
  writeln(i);

 compiles but I get nothing.

foreach_reverse(i; 1 .. 20)
     writeln(i);

Or:

import std.range : iota, retro;
foreach(i; iota(1, 20).retro)
     writeln(i);

But if you really want the numbers 1 to 20, you should use 21 as 
the end value in both cases, as it's exclusive.

Namal <sotis22 mail.ru> writes:

Hello guys,

I remember it is possible to get the index for each element in 
the foreach loop, but I forgot how to do it. Can you help me out 
please. Thx.

wobbles <grogan.colin gmail.com> writes:

On Tuesday, 3 November 2015 at 14:47:14 UTC, Namal wrote:
 Hello guys,

 I remember it is possible to get the index for each element in 
 the foreach loop, but I forgot how to do it. Can you help me 
 out please. Thx.

auto arr = ["Hello", "World"];

foreach(int idx, string str; arr){
    writefln("%s = %s", idx, str);
}

Adam D. Ruppe <destructionator gmail.com> writes:

On Tuesday, 3 November 2015 at 14:47:14 UTC, Namal wrote:
 I remember it is possible to get the index for each element in 
 the foreach loop, but I forgot how to do it. Can you help me 
 out please. Thx.

for many of them it is as simple as:

foreach(index, element; array) { }

Namal <sotis22 mail.ru> writes:

On Tuesday, 3 November 2015 at 14:52:19 UTC, Adam D. Ruppe wrote:
 On Tuesday, 3 November 2015 at 14:47:14 UTC, Namal wrote:
 I remember it is possible to get the index for each element in 
 the foreach loop, but I forgot how to do it. Can you help me 
 out please. Thx.

 for many of them it is as simple as:

 foreach(index, element; array) { }

Thank you. I am still struggling with the functional ways of D. 
Now how could I write this foreach loop the functional way?

bool[] arr = [ture, false, ture, ...];

int count;
foreach(i;arr){

   if(!i)
     count++;
}
writeln(count);

wobbles <grogan.colin gmail.com> writes:

On Tuesday, 3 November 2015 at 15:06:00 UTC, Namal wrote:
 On Tuesday, 3 November 2015 at 14:52:19 UTC, Adam D. Ruppe 
 wrote:
 On Tuesday, 3 November 2015 at 14:47:14 UTC, Namal wrote:
 I remember it is possible to get the index for each element 
 in the foreach loop, but I forgot how to do it. Can you help 
 me out please. Thx.

 for many of them it is as simple as:

 foreach(index, element; array) { }

 Thank you. I am still struggling with the functional ways of D. 
 Now how could I write this foreach loop the functional way?

 bool[] arr = [ture, false, ture, ...];

 int count;
 foreach(i;arr){

   if(!i)
     count++;
 }
 writeln(count);

writefln("Count is: %s", arr
   .filter!(a => a==true)
   .sum);

// Note: std.algorithm.sum is the same as
// std.algorithm.reduce!((a,b)=a+b);

wobbles <grogan.colin gmail.com> writes:

On Tuesday, 3 November 2015 at 15:10:43 UTC, wobbles wrote:
 On Tuesday, 3 November 2015 at 15:06:00 UTC, Namal wrote:
 On Tuesday, 3 November 2015 at 14:52:19 UTC, Adam D. Ruppe 
 wrote:
 On Tuesday, 3 November 2015 at 14:47:14 UTC, Namal wrote:
 [...]

 for many of them it is as simple as:

 foreach(index, element; array) { }

 Thank you. I am still struggling with the functional ways of 
 D. Now how could I write this foreach loop the functional way?

 bool[] arr = [ture, false, ture, ...];

 int count;
 foreach(i;arr){

   if(!i)
     count++;
 }
 writeln(count);

 writefln("Count is: %s", arr
   .filter!(a => a==true)
   .sum);

 // Note: std.algorithm.sum is the same as
 // std.algorithm.reduce!((a,b)=a+b);

Oh, I realise now you were counting the number of 'false' values.
I counted the true values - so the filter line is wrong here.

Namal <sotis22 mail.ru> writes:

On Tuesday, 3 November 2015 at 15:10:43 UTC, wobbles wrote:
 On Tuesday, 3 November 2015 at 15:06:00 UTC, Namal wrote:
 On Tuesday, 3 November 2015 at 14:52:19 UTC, Adam D. Ruppe 
 wrote:
 On Tuesday, 3 November 2015 at 14:47:14 UTC, Namal wrote:
 I remember it is possible to get the index for each element 
 in the foreach loop, but I forgot how to do it. Can you help 
 me out please. Thx.

 for many of them it is as simple as:

 foreach(index, element; array) { }

 Thank you. I am still struggling with the functional ways of 
 D. Now how could I write this foreach loop the functional way?

 bool[] arr = [ture, false, ture, ...];

 int count;
 foreach(i;arr){

   if(!i)
     count++;
 }
 writeln(count);

 writefln("Count is: %s", arr
   .filter!(a => a==true)
   .sum);

 // Note: std.algorithm.sum is the same as
 // std.algorithm.reduce!((a,b)=a+b);

How do I save sum as integer or something I try;

	arr.writeln;
	return arr.filter!(a=>a==false).sum;

but I get
[true, false, true, false, true, true, true, false, true, false]
0

Namal <sotis22 mail.ru> writes:

On Tuesday, 3 November 2015 at 15:10:43 UTC, wobbles wrote:
 On Tuesday, 3 November 2015 at 15:06:00 UTC, Namal wrote:
 On Tuesday, 3 November 2015 at 14:52:19 UTC, Adam D. Ruppe 
 wrote:
 On Tuesday, 3 November 2015 at 14:47:14 UTC, Namal wrote:
 I remember it is possible to get the index for each element 
 in the foreach loop, but I forgot how to do it. Can you help 
 me out please. Thx.

 for many of them it is as simple as:

 foreach(index, element; array) { }

 Thank you. I am still struggling with the functional ways of 
 D. Now how could I write this foreach loop the functional way?

 bool[] arr = [ture, false, ture, ...];

 int count;
 foreach(i;arr){

   if(!i)
     count++;
 }
 writeln(count);

 writefln("Count is: %s", arr
   .filter!(a => a==true)
   .sum);

 // Note: std.algorithm.sum is the same as
 // std.algorithm.reduce!((a,b)=a+b);

well I tried this that way, but my count stays 0, same as if I do 
it in an int function with a return though I clearly have some 
false elements in the arr.

Edwin van Leeuwen <edder tkwsping.nl> writes:

On Tuesday, 3 November 2015 at 15:29:31 UTC, Namal wrote:
 writefln("Count is: %s", arr
   .filter!(a => a==true)
   .sum);

 // Note: std.algorithm.sum is the same as
 // std.algorithm.reduce!((a,b)=a+b);


Shouldn't you be using walkLength instead of sum, since you are 
counting the left over values?

import std.range : walkLength;
writefln("Count is: %s", arr
   .filter!(a => a==false)
   .walkLength);

wobbles <grogan.colin gmail.com> writes:

On Tuesday, 3 November 2015 at 15:42:16 UTC, Edwin van Leeuwen 
wrote:
 On Tuesday, 3 November 2015 at 15:29:31 UTC, Namal wrote:
 writefln("Count is: %s", arr
   .filter!(a => a==true)
   .sum);

 // Note: std.algorithm.sum is the same as
 // std.algorithm.reduce!((a,b)=a+b);


 Shouldn't you be using walkLength instead of sum, since you are 
 counting the left over values?

 import std.range : walkLength;
 writefln("Count is: %s", arr
   .filter!(a => a==false)
   .walkLength);

That would work also yes.
Be interesting to know which is more efficient actually - I 
suspect they're very similar.

Edwin van Leeuwen <edder tkwsping.nl> writes:

On Tuesday, 3 November 2015 at 16:55:44 UTC, wobbles wrote:
 On Tuesday, 3 November 2015 at 15:42:16 UTC, Edwin van Leeuwen 
 wrote:
 On Tuesday, 3 November 2015 at 15:29:31 UTC, Namal wrote:
 writefln("Count is: %s", arr
   .filter!(a => a==true)
   .sum);

 // Note: std.algorithm.sum is the same as
 // std.algorithm.reduce!((a,b)=a+b);


 Shouldn't you be using walkLength instead of sum, since you 
 are counting the left over values?

 import std.range : walkLength;
 writefln("Count is: %s", arr
   .filter!(a => a==false)
   .walkLength);

 That would work also yes.
 Be interesting to know which is more efficient actually - I 
 suspect they're very similar.

false converts to zero, so
[false,false,false].sum == 0

Of course true converts to one ->
[true,true,true].sum == 3

TheFlyingFiddle <borin.lukas gmail.com> writes:

On Tuesday, 3 November 2015 at 15:29:31 UTC, Namal wrote:
 well I tried this that way, but my count stays 0, same as if I 
 do it in an int function with a return though I clearly have 
 some false elements in the arr.

You could also use count: 
http://dlang.org/phobos/std_algorithm_searching.html#count

return arr.count!(x => !x);

ixid <adamsibson hotmail.com> writes:

On Tuesday, 3 November 2015 at 15:06:00 UTC, Namal wrote:
Can you help me out please. Thx.


reduce!((x, y) => x + !y)(0, arr).writeln;

This would probably be the preferred way, that uses a lambda 
function (x, y) => x + !y which adds the inverse of the next 
array value (y) to the total so far (x). You have to provide 0 as 
the first argument to reduce as it is the seed, otherwise it will 
use the first value in the array as the seed and convert it to an 
int, making the total 1 too high as the first value is 'true'.

You can also use a string but this is frowned on style-wise 
though in this case it is clearer:

reduce!"a + !b"(0, arr).writeln;