问题
I was wondering if .NET offers any standard functionality for doing a prefix search through a list or a dictionary object. I came across the StringDictionary, but couldn't figure out if it can do that for me.
And if it can do a prefix search, can it also do substring search or let me search using something like a regular expression?
Thanks in advance.
回答1:
StringDictionary is merely a hash table where the keys and values are strings. This existed before generics (when Dictionary<string, string> was not possible).
The data structure that you want here is a trie. There are implementations on CodeProject:
- Phone Directory Implementation Using TRIE
- A Reusable Prefix Tree using Generics in C# 2.0
Or, if you're that kind of guy, roll your own (see CLRS).
回答2:
I don't believe StringDictionary supports a prefix search, but if you use a SortedList<,> you can binary search through the range of keys until you find the first entry before and after your prefix.
回答3:
I think the StringDictionary is old school (pre-generics). You should probably use a Dictionary(Of String, String) instead because it implements IEnumerable (think LINQ). One extremely lame thing about StringDictionary is that it's case-insensitive.
回答4:
I made a generic implementation of this available here.
Since string implements IEnumerable<char>, you can use it with char as parameter for TKeyElement.
来源：https://stackoverflow.com/questions/1902108/prefix-search-through-list-dictionary-using-net-stringdictionary