具有可变维度的 JavaScript 函数数组

Question

我正在编写一个函数，它在更多维度上索引一维数组。用户可以选择索引的深度。

例如。

var store = ["Alaska", "Alabama", "North Korea", "South Korea"];

用户可以选择例如深度1。这意味着它将以字符串的第一个字符作为索引

index["a"] = ["Alaska", "Alabama"];
index["n"] = ["North Korea"];

如果用户选择 depth = 2 则它将是索引为两个开始字符的二维数组

index["a"]["l"] = ["Alaska", "Alabama"];

等等

我如何在 JavaScript 中完成一个可以填充变量维度数组的函数？

var indexthis = function(store,depth)
{
  if(depth == "undefined")
  {depth =1;}
//any Suggestions to go on?
};

问候

Answer 1

这个函数:

function indexWord(index, word, letters) {
    var letter;
    if (!letters) letters = word.split("");
    while (letters.length) {
        letter = letters.shift().toLowerCase();
        if (!(letter in index)) index[letter] = {_items: []};
        index[letter]._items.push(word);
        indexWord(index[letter], word, letters);
    }
}

这样调用:

var store = ["Alaska", "Alabama", "North Korea", "South Korea"],
    index = {}, i;

for (i = 0; i < store.length; i++) {
    indexWord(index, store[i]);
}

为您提供以下索引:

{
  a: {
    _items: ["Alaska", "Alabama"],
    l: {
      _items: ["Alaska", "Alabama"],
      a: {
        _items: ["Alaska", "Alabama"],
        s: {
          _items: ["Alaska"],
          k: {
            _items: ["Alaska"],
            a: {
              _items: ["Alaska"]
            }
          }
        },
        b: {
          _items: ["Alabama"],
          a: {
            _items: ["Alabama"],
            m: {
              _items: ["Alabama"],
              a: {
                _items: ["Alabama"]
              }
            }
          }
        }
      }
    }
  },
  n: {
    _items: ["North Korea"],
    o: {
      _items: ["North Korea"],
      r: {
        _items: ["North Korea"],
        t: {
          _items: ["North Korea"],
          h: {
            _items: ["North Korea"],
            " ": {
              _items: ["North Korea"],
              k: {
                _items: ["North Korea"],
                o: {
                  _items: ["North Korea"],
                  r: {
                    _items: ["North Korea"],
                    e: {
                      _items: ["North Korea"],
                      a: {
                        _items: ["North Korea"]
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  },
  s: {
    _items: ["South Korea"],
    o: {
      _items: ["South Korea"],
      u: {
        _items: ["South Korea"],
        t: {
          _items: ["South Korea"],
          h: {
            _items: ["South Korea"],
            " ": {
              _items: ["South Korea"],
              k: {
                _items: ["South Korea"],
                o: {
                  _items: ["South Korea"],
                  r: {
                    _items: ["South Korea"],
                    e: {
                      _items: ["South Korea"],
                      a: {
                        _items: ["South Korea"]
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}

其中 index["a"]["l"]._items 或 index.a.l._items 可用于访问 ["Alaska", “阿拉巴马州”]。