• Gary Willoughby (11/11) Jun 21 2013 Have you any tips for using D when you need fast string
• Vladimir Panteleev (3/4) Jun 21 2013 You'll want to use appender, from std.array:
• Jonathan M Davis (7/23) Jun 21 2013 In general, ~= will be faster, beacause it won't create temporaries like...
• Steven Schveighoffer (6/25) Jun 21 2013 I believe the above is one call to the runtime.
• monarch_dodra (3/14) Jun 21 2013 Regardless of whether you end up using lots of ~=, or Appender
• John Colvin (3/22) Jun 21 2013 It's worth pointing out that Appender supports ~= so it's very
• Namespace (1/3) Jun 21 2013 This works since 2.062 AFAIK. So is still quite new.

"Gary Willoughby" <dev kalekold.net> writes:

Have you any tips for using D when you need fast string 
concatenation? I regularly use code like this:

     foreach (i, range)
     {
         foo ~= bar;
     }

or:

     foo = foo ~ bar ~ baz ~ qux;

I've used std.string.format(...) in some instances which sped 
things up which surprised me.

Are there faster ways of appending strings?

"Vladimir Panteleev" <vladimir thecybershadow.net> writes:

On Friday, 21 June 2013 at 10:09:10 UTC, Gary Willoughby wrote:
 Are there faster ways of appending strings?

You'll want to use appender, from std.array:

Jonathan M Davis <jmdavisProg gmx.com> writes:

On Friday, June 21, 2013 12:09:09 Gary Willoughby wrote:
 Have you any tips for using D when you need fast string
 concatenation? I regularly use code like this:
 
      foreach (i, range)
      {
          foo ~= bar;
      }
 
 or:
 
      foo = foo ~ bar ~ baz ~ qux;
 
 I've used std.string.format(...) in some instances which sped
 things up which surprised me.
 
 Are there faster ways of appending strings?

In general, ~= will be faster, beacause it won't create temporaries like 
concatenating a bunch of strings in a single expression would. However, if you 
want faster appending, generally the thing to use is std.array.Appender. And 
if you want to use format strings, it can be used with 
std.format.formattedWrite.

- Jonathan M Davis

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

On Fri, 21 Jun 2013 06:14:38 -0400, Jonathan M Davis <jmdavisProg gmx.com>  
wrote:

 On Friday, June 21, 2013 12:09:09 Gary Willoughby wrote:
 Have you any tips for using D when you need fast string
 concatenation? I regularly use code like this:

      foreach (i, range)
      {
          foo ~= bar;
      }

 or:

      foo = foo ~ bar ~ baz ~ qux;

 I've used std.string.format(...) in some instances which sped
 things up which surprised me.

 Are there faster ways of appending strings?

 In general, ~= will be faster, beacause it won't create temporaries like
 concatenating a bunch of strings in a single expression would.

I believe the above is one call to the runtime.

To answer the OP, using reserve will speed up the allocation quite a bit.   
Appender is certainly the fastest method.

-Steve

"monarch_dodra" <monarchdodra gmail.com> writes:

On Friday, 21 June 2013 at 10:09:10 UTC, Gary Willoughby wrote:
 Have you any tips for using D when you need fast string 
 concatenation? I regularly use code like this:

     foreach (i, range)
     {
         foo ~= bar;
     }

 or:

     foo = foo ~ bar ~ baz ~ qux;

 I've used std.string.format(...) in some instances which sped 
 things up which surprised me.

 Are there faster ways of appending strings?

Regardless of whether you end up using lots of ~=, or Appender 
(possibly with formattedWrite), using reserve never hurts.

"John Colvin" <john.loughran.colvin gmail.com> writes:

On Friday, 21 June 2013 at 11:33:29 UTC, monarch_dodra wrote:
 On Friday, 21 June 2013 at 10:09:10 UTC, Gary Willoughby wrote:
 Have you any tips for using D when you need fast string 
 concatenation? I regularly use code like this:

    foreach (i, range)
    {
        foo ~= bar;
    }

 or:

    foo = foo ~ bar ~ baz ~ qux;

 I've used std.string.format(...) in some instances which sped 
 things up which surprised me.

 Are there faster ways of appending strings?

 Regardless of whether you end up using lots of ~=, or Appender 
 (possibly with formattedWrite), using reserve never hurts.


It's worth pointing out that Appender supports ~= so it's very 
easy to swap it in, replacing builtin concatenation.

"Namespace" <rswhite4 googlemail.com> writes:

 It's worth pointing out that Appender supports ~= so it's very 
 easy to swap it in, replacing builtin concatenation.

This works since 2.062 AFAIK. So is still quite new.