Is there a natural way of generating/filling a string/wstring/dstring of a specific length with random contents?

Nordlöw:

> Is there a natural way of generating/filling a string/wstring/dstring of a specific length with random contents?

Do you mean something like this?


import std.stdio, std.random, std.ascii, std.range, std.conv;

string genRandomString(in size_t len) {
    return len
           .iota
           .map!(_ => lowercase[uniform(0, $)])
           .text;
}

void main() {
    import std.stdio;

    10.genRandomString.writeln;
}


Bye,
bearophile

On Monday, 14 July 2014 at 22:21:36 UTC, bearophile wrote:
> Nordlöw:
>
>> Is there a natural way of generating/filling a string/wstring/dstring of a specific length with random contents?
>
> Do you mean something like this?
>
>
> import std.stdio, std.random, std.ascii, std.range, std.conv;
>
> string genRandomString(in size_t len) {
>     return len
>            .iota
>            .map!(_ => lowercase[uniform(0, $)])
>            .text;
> }
>
> void main() {
>     import std.stdio;
>
>     10.genRandomString.writeln;
> }
>
>
> Bye,
> bearophile

Alternative:

randomSample(lowercase, 10, lowercase.length).writeln;

On Monday, 14 July 2014 at 22:27:57 UTC, Brad Anderson wrote:
>
> Alternative:
>
> randomSample(lowercase, 10, lowercase.length).writeln;

std.ascii should really be using std.encoding.AsciiString. Then
that length wouldn't be necessary.

Brad Anderson:

> Alternative:
>
> randomSample(lowercase, 10, lowercase.length).writeln;

From randomSample docs:

>Selects a random subsample out of r, containing exactly n elements. The order of elements is the same as in the original range.<

Bye,
bearophile

On Monday, 14 July 2014 at 22:21:36 UTC, bearophile wrote:
> Nordlöw:
>
>> Is there a natural way of generating/filling a string/wstring/dstring of a specific length with random contents?
>
> Do you mean something like this?
>
>
> import std.stdio, std.random, std.ascii, std.range, std.conv;
>
> string genRandomString(in size_t len) {
>     return len
>            .iota
>            .map!(_ => lowercase[uniform(0, $)])
>            .text;
> }
>
> void main() {
>     import std.stdio;
>
>     10.genRandomString.writeln;
> }
>
>
> Bye,
> bearophile

I was specifically interested in something that exercises (random samples) potentially _all_ code points for string, wstring and dstring (all code units that is).

On Monday, 14 July 2014 at 22:32:51 UTC, Nordlöw wrote:

I believe defining a complete random sampling of all code units in dchar is a good start right? This can then be reused to lazily convert while filling in a string and wstring.

Nordlöw:

> I was specifically interested in something that exercises (random samples) potentially _all_ code points for string, wstring and dstring (all code units that is).

That's harder. Generating all uints and then testing if it's a Unicode dchar seems possible.

Bye,
bearophile

On Monday, 14 July 2014 at 22:35:59 UTC, Nordlöw wrote:
> On Monday, 14 July 2014 at 22:32:51 UTC, Nordlöw wrote:
>
> I believe defining a complete random sampling of all code units in dchar is a good start right? This can then be reused to lazily convert while filling in a string and wstring.

isValidCodePoint()

at

http://dlang.org/phobos/std_encoding.html

might be were to start.

Nordlöw:

> I believe defining a complete random sampling of all code units in dchar is a good start right? This can then be reused to lazily convert while filling in a string and wstring.

Several combinations of unicode chars are not meaningful/valid (like pairs of ligatures). Any thing that has to work correctly with Unicode is complex.

Bye,
bearophile