d转换数组到类似集

原文

import std;
auto deduplicate(R)(R input)if (isInputRange!R)
{
    alias Unit = void[0];
    enum unit = Unit.init;
    Unit[ElementType!R] seen;
    return input.filter!((e) {
        if (e in seen) return false;
        seen[e] = unit;
        return true;
    });
}
unittest {
    assert([ 1, 2, 3, 4, 2, 5, 6, 4, 7 ].deduplicate.array ==[ 1, 2, 3, 4, 5, 6, 7 ]);
    assert([ "abc", "def", "def", "ghi", "abc", "jkl" ].deduplicate.array ==[ "abc", "def", "ghi", "jkl" ]);
}

或:

int[] someArray = [5, 3, 8, 5, 2, 3, 0, 8];
int[] uniqueArray;
uniqueArray = uniq(sort(someArray)).array; // 注意排序
writeln(uniqueArray); // [0, 2, 3, 5, 8]

或:

import std;

auto str = "D语言";

void main()
{
  size_t i;
  str.map!(n => tuple(n, i++))
     .assocArray.keys
     .sort.writeln; // 
}
//
auto set(R)(R[] list) {
  size_t[R] result;
  foreach(i, item; list) {
    result[item] = i;
  }
  return result.keys;
}

unittest
{
  auto xRay = set(str.dup);
  xRay.array.sort.writeln; 
}