您可以使用new Dictionary<string,(string CaseSensitiveKey,T Data)，其中键总是小写（见下文），但是...
A.用户更友好的搜索 string.Contains 或 Regex.IsMatch
（我后来添加了这个）
我认为您最终可能会使用string.Contains（甚至可能是Regex.IsMatch），以便您的搜索可以捕获部分匹配项。
Regex.IsMatch
var d = new Dictionary<string, string>() {
{ "First Last", "Some data" },
{ "Fir La", "Some data 2" } };
while (true)
{
var term = Console.ReadLine();
// Case-sensitive flag would control RegexOptions
var results = d.Where( kvp => Regex.IsMatch(kvp.Key, term, RegexOptions.IgnoreCase)).ToList();
if (results.Any())
foreach (var kvp in results)
Console.WriteLine($"\t{kvp.Key}:{kvp.Value}");
else
Console.WriteLine("Not found");
}
fi.*la
First Last:Some data
Fir La:Some data 2
fir.*t
First Last:Some data
包含
// Case-sensitive flag would control `StrinComparison` flag.
var results = d.Where(
kvp => kvp.Key.ToLower().Contains(term.ToLower(), StringComparison.InvariantCultureIgnoreCase))
.ToList();
}
Fi
Found First Last:Some data
Found Fir La:Some data 2
First
Found First Last:Some data
Fal
Not found
B.我想要字典搜索。和快速
您可以使用new Dictionary<string,(string CaseSensitiveKey,T Data)，其中键始终为小写。
如果字典中可能有“Gerardo Grignoli”和“gerardo grignoli”，这将不起作用，但我怀疑您的情况并非如此，因为如果您要查找键，你不是在部分匹配之后。这显然只是一个假设。
如果您想要快速解决完全匹配并处理仅因大小写而异的条目，请参阅Dictionary<string, Dictionary<string, TValue>> 的其他答案。
public static T LowerCaseKeyWay<T>(Dictionary<string, (string CaseSensitiveKey, T Data)> d, string term, bool isCS)
=> d.TryGetValue(term.ToLower(), out var item)
? !isCS
? item.Data
: term == item.CaseSensitiveKey ? item.Data : default
: default;
使用示例。
class SO
{
public int Number { get; set; }
public int Rep { get; set; }
}
public static void Main(string[] args)
{
var d = new Dictionary<string,(string CaseSensitiveKey,SO Data)>() {
{ "Gerardo Grignoli".ToLower(), ("Gerardo Grignoli", new SO { Number=97471, Rep=7987} )},
{ "John Wu".ToLower(), ("John Wu", new SO { Number=2791540, Rep=34973})}
};
foreach( var searchTerm in new []{ "Gerardo Grignoli", "Gerardo Grignoli".ToLower()} )
foreach( var isSearchCaseSensitive in new[]{true,false} ) {
Console.WriteLine($"{searchTerm}/case-sensitive:{isSearchCaseSensitive}: {Search(d, searchTerm, isSearchCaseSensitive)?.Rep}");
}
}
输出
Gerardo Grignoli/case-sensitive:True: 7987
Gerardo Grignoli/case-sensitive:False: 7987
gerardo grignoli/case-sensitive:True:
gerardo grignoli/case-sensitive:False: 7987
原始速度测试
结果
noOfSearches: 1000
noOfItems: 100
Lowercase key way: Elapsed 4ms, count found: 1500
Linq way Elapsed 57ms, count found: 1500
noOfSearches: 1000
noOfItems: 1000
Lowercase key way: Elapsed 3ms, count found: 3000
Linq way Elapsed 454ms, count found: 3000
noOfSearches: 10000
noOfItems: 100
Lowercase key way: Elapsed 11ms, count found: 15000
Linq way Elapsed 447ms, count found: 15000
noOfSearches: 10000
noOfItems: 1000
Lowercase key way: Elapsed 10ms, count found: 15000
Linq way Elapsed 5156ms, count found: 15000
noOfSearches: 100000
noOfItems: 100
Lowercase key way: Elapsed 113ms, count found: 150000
Linq way Elapsed 5059ms, count found: 150000
noOfSearches: 100000
noOfItems: 1000
Lowercase key way: Elapsed 83ms, count found: 150000
Linq way Elapsed 48855ms, count found: 150000
noOfSearches: 1000000
noOfItems: 100
Lowercase key way: Elapsed 1279ms, count found: 1500000
Linq way Elapsed 49558ms, count found: 1500000
noOfSearches: 1000000
noOfItems: 1000
Lowercase key way: Elapsed 961ms, count found: 1500000
(...)
测试代码（我很高兴它被撕开）
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
namespace ConsoleApp4
{
class SO
{
public int Number { get; set; }
public int Rep { get; set; }
}
class Program
{
public static void Main(string[] args)
{
// Preload linq
var _ = new []{"•`_´•"}.FirstOrDefault( k => k == "(O_O)" );
foreach( int noOfSearches in new []{1000, 10000, 100000, 1000000} )
foreach( int noOfItems in new []{100, 1000} )
{
var d1 = new Dictionary<string, SO>();
for(int i = 0; i < noOfItems; i++) {
d1.Add($"Name {i}", new SO {Number = i, Rep = i *2});
}
var d2 = new Dictionary<string, (string CaseSensitiveKey, SO Data)>();
foreach (var entry in d1)
{
d2.Add(entry.Key.ToLower(), (entry.Key, entry.Value));
}
Console.WriteLine($"noOfSearches: {noOfSearches}");
Console.WriteLine($" noOfItems: {noOfItems}");
Console.Write(" Lowercase key way:".PadRight(30));
PrimitiveSpeedTest( (term, isCS) => LowerCaseKeyWay(d2, term, isCS), noOfItems, noOfSearches);
Console.Write(" Linq way".PadRight(30));
PrimitiveSpeedTest( (term, isCS) => LinqWay(d1, term, isCS), noOfItems, noOfSearches);
}
}
private static void PrimitiveSpeedTest(Func<string, bool, SO> search, int noOfItems, int noOfSearches)
{
var count = 0;
Stopwatch sw = Stopwatch.StartNew();
for (int i = 0; i < noOfSearches; i++)
{
var originalTerm = $"Name {i % (noOfItems*2)}"; // Some found, some not found
foreach (var term in new[] { originalTerm, originalTerm.ToLower() })
foreach (var isCS in new[] { true, false })
{
var so = search(term, isCS);
if (so != null) count++;
//Console.WriteLine($"{term}/case-sensitive:{isCS}: {Search(d, term, isCS)?.Rep}");
}
}
var elapsed = sw.Elapsed;
Console.WriteLine($"Elapsed {sw.ElapsedMilliseconds}ms, count found: {count} ");
}
public static SO LowerCaseKeyWay(Dictionary<string, (string CaseSensitiveKey, SO Data)> d, string term, bool isCS)
=> d.TryGetValue(term.ToLower(), out var item)
? !isCS
? item.Data
: term == item.CaseSensitiveKey ? item.Data : null
: null;
static public T LinqWay<T>(Dictionary<string,T> source, string key, bool caseSensitive)
{
//Original: if (caseSensitive) return source[key];
if(caseSensitive) return source.ContainsKey(key) ? source[key] : default;
key = source.Keys.FirstOrDefault( k => String.Compare(key, k, StringComparison.CurrentCultureIgnoreCase) == 0);
//Original: if (key == null) throw new KeyNotFoundException();
if (key == null) return default;
return source[key];
}
}
}