On Saturday, 22 January 2022 at 01:33:16 UTC, Steven
Schveighoffer wrote:
so I why watching this video by Andrei:
https://www.youtube.com/watch?v=mCrVYYlFTrA
In it, he talked about writing the simplest design that could
possibly work....
Which got me thinking....
// ----
module test;
@safe:
import std.stdio : write, writef, writeln, writefln;
import std.range : iota, enumerate;
import std.array : array, byPair, Appender, appender;
import std.random : Random, unpredictableSeed, dice, randomCover;
import std.algorithm : map;
import std.conv : to;
import std.format;
import std.stdio : File;
import std.file : exists;
import std.exception : enforce;
import std.meta : Alias;
debug { import std; }
Random rnd;
static this() { rnd = Random(unpredictableSeed); }
void main(string[] args)
{
int recordsNeeded, valuesPerRecord;
string fname;
if(args.length < 4) // then set defaults
{
recordsNeeded = 10;
valuesPerRecord= 8;
version(Windows) { fname = "D:/rnd_records.txt"; }
version(linux) { fname = "./rnd_records.txt"; }
}
else
{
// assumes valid values being passed in ;-)
recordsNeeded = to!int(args[1]);
valuesPerRecord = to!int(args[2]);
fname = args[3];
}
debug
{ writefln("%s records (where a record is: id and %s
values), will be written to file: %s", recordsNeeded,
valuesPerRecord, fname); }
else
{
enforce(!exists(fname), "Oops! That file already
exists!");
enforce(recordsNeeded <= 1_000_000_000, "C'mon!
That's too many records!");
}
CreateDataFile(recordsNeeded, valuesPerRecord, fname);
writefln("All done. Check if records written to %s", fname);
}
void CreateDataFile(const(int) recordsNeeded, const(int)
valuesPerRecord, const(string) fname)
{
auto file = File(fname, "w");
scope(exit) file.close;
Appender!string bigString = appender!string;
bigString.reserve(recordsNeeded);
const int iotaStartNum = 100_000_001;
foreach(i, id; iota(iotaStartNum, iotaStartNum +
recordsNeeded).enumerate)
{
bigString
~= id.to!string
~ ","
~ valuesPerRecord.iota.map!(valuesPerRecord =>
cast(int)rnd.dice(0.6, 1.4)).format!"%(%s,%)"
~ "\n";
}
file.write(bigString[]);
}
// ----