Re: Custom separator in array format

[Malte via Digitalmars-d-learn]

On Tuesday, 28 January 2020 at 08:54:16 UTC, Simen Kjærås wrote:

import std.stdio : writefln;
import std.format : format;
import std.algorithm : map;

auto vec = [1000, 2000, 3000];

writefln("%-(%s\t%)", vec.map!(e => format!"%,2?d"('_', 
e)));




That helps, thank you very much.

Re: Custom separator in array format

[Simen Kjærås via Digitalmars-d-learn]

On Tuesday, 28 January 2020 at 07:36:25 UTC, Malte wrote:
I want to format an array using the %(...%) syntax. How can I 
change the separator? I tried to use ? and add it as additional 
parameter, but that doesn't seem to work on arrays:


import std;
void main()
{
writeln("This works:");
writefln("%,2?d", '_', 2000); // 20_00

auto vec = [1000, 2000, 3000];
writeln("This should fail (separator character expected) 
but the ? is just ignored:");

writefln("%(%,2?d\t%)", vec); // 10,0020,00   30,00
writeln("This throws:");
writefln("%(%,2?d\t%)", '_', vec); // 
std.format.FormatException@/dlang/dmd/linux/bin64/../../src/phobos/std/format.d(2271): incompatible format character for integral argument: %(

}


I think I see why it's not working. Essentially, for each element 
of vec, format is called with only that element as an argument. 
Essentially, rather than:


foreach (e; vec)
writef("%,2?d\t", '_', e);
writeln();

You get:

foreach (e; vec)
writef("%,2?d\t", e);
writeln();

For whatever reason, it doesn't throw when missing an argument 
for the separator - I'd say this is a bug 
(https://issues.dlang.org/show_bug.cgi?id=20541).


For now, you can work around the issue this way:

import std.stdio : writefln;
import std.format : format;
import std.algorithm : map;

auto vec = [1000, 2000, 3000];

writefln("%-(%s\t%)", vec.map!(e => format!"%,2?d"('_', e)));

--
  Simen

Custom separator in array format

[Malte via Digitalmars-d-learn]

I want to format an array using the %(...%) syntax. How can I 
change the separator? I tried to use ? and add it as additional 
parameter, but that doesn't seem to work on arrays:


import std;
void main()
{
writeln("This works:");
writefln("%,2?d", '_', 2000); // 20_00

auto vec = [1000, 2000, 3000];
writeln("This should fail (separator character expected) but 
the ? is just ignored:");

writefln("%(%,2?d\t%)", vec); // 10,0020,00   30,00
writeln("This throws:");
writefln("%(%,2?d\t%)", '_', vec); // 
std.format.FormatException@/dlang/dmd/linux/bin64/../../src/phobos/std/format.d(2271): incompatible format character for integral argument: %(

}