Question

在Google中搜索邮件时，我们使用sytax

from:devcoder hasattachments:true mySearchString on:11-aug

或

mySearchString from:devcoder on:11-aug anotherSearchKeyword

解析之后，我应该得到keyvalue对，例如（from，devcoder），（on，11-aug）。在c＃中实现此解析的最佳方法是什么。

Answer 1

对Linq-ify Jason的回答：

string s = "from:devcoder hasattachments:true mySearchString on:11-aug";

var keyValuePairs = s.Split(' ')
    .Select(x => x.Split(':'))
    .Where(x => x.Length == 2)
    .ToDictionary(x => x.First(), x => x.Last());

Answer 2

按空格拆分，然后对于拆分的每个组件，将其拆分为:。然后继续进行。大致是：

string s = "from:devcoder hasattachments:true mySearchString on:11-aug";
var components = s.Split(' ');
var blocks = components.Select(component => component.Split(':'));
foreach(var block in blocks) {
    if(block.Length == 1) {
        Console.WriteLine("Found {0}", block[0]);
    }
    else {
        Console.WriteLine(
            "Found key-value pair key = {0}, value = {1}",
            block[0],
            block[1]
        );
    }
}

输出：

Found key-value pair key = from, value = devcoder
Found key-value pair key = hasattachments, value = true
Found mySearchString
Found key-value pair key = on, value = 11-aug

第二个字符串的输出：

Found mySearchString
Found key-value pair key = from, value = devcoder
Found key-value pair key = on, value = 11-aug
Found anotherSearchKeyword

Answer 3

这是我过去使用的一种基于正则表达式的方法;它支持前缀和带引号的字符串。

更正确/更健壮/更高效的方法将涉及编写一个简单的解析器，但是在大多数使用场景中，与实现和测试解析器相关的时间和精力将与收益大不相称。

private static readonly Regex searchTermRegex = new Regex(
        @"^(
            \s*
            (?<term>
                ((?<prefix>[a-zA-Z][a-zA-Z0-9-_]*):)?
                (?<termString>
                    (?<quotedTerm>
                        (?<quote>['""])
                        ((\\\k<quote>)|((?!\k<quote>).))*
                        \k<quote>?
                    )
                    |(?<simpleTerm>[^\s]+)
                )
            )
            \s*
        )*$",
        RegexOptions.Compiled | RegexOptions.Singleline | RegexOptions.IgnorePatternWhitespace | RegexOptions.ExplicitCapture
    );


private static void FindTerms(string s) {
    Console.WriteLine("[" + s + "]");
    Match match = searchTermRegex.Match(s);
    foreach(Capture term in match.Groups["term"].Captures) {
        Console.WriteLine("term: " + term.Value);

        Capture prefix = null;
        foreach(Capture prefixMatch in match.Groups["prefix"].Captures)
            if(prefixMatch.Index >= term.Index && prefixMatch.Index <= term.Index + term.Length) {
                prefix = prefixMatch;
                break;
            }

        if(null != prefix)
            Console.WriteLine("prefix: " + prefix.Value);

        Capture termString = null;
        foreach(Capture termStringMatch in match.Groups["termString"].Captures)
            if(termStringMatch.Index >= term.Index && termStringMatch.Index <= term.Index + term.Length) {
                termString = termStringMatch;
                break;
            }
        Console.WriteLine("termString: " + termString.Value);
    }
    Console.WriteLine();
}

public static void Main (string[] args)
{           
    FindTerms(@"two terms");
    FindTerms(@"prefix:value");
    FindTerms(@"some:""quoted term""");
    FindTerms(@"firstname:Jack ""the Ripper""");
    FindTerms(@"'quoted term\'s escaped quotes'");
    FindTerms(@"""unterminated quoted string");
}

输出：

[two terms]
term: two
termString: two
term: terms
termString: terms

[prefix:value]
term: prefix:value
prefix: prefix
termString: value

[some:"quoted term"]
term: some:"quoted term"
prefix: some
termString: "quoted term"

[firstname:Jack "the Ripper"]
term: firstname:Jack
prefix: firstname
termString: Jack
term: "the Ripper"
termString: "the Ripper"

['quoted term\'s escaped quotes']
term: 'quoted term\'s escaped quotes'
termString: 'quoted term\'s escaped quotes'

["unterminated quoted string]
term: "unterminated quoted string
termString: "unterminated quoted string

Answer 4

空间上的第一个Split()，然后你有一个包含所有搜索词的数组。然后循环遍历它们以在冒号上再次找到Contains()冒号（:)和Split()的那些。

如何解析字符串以查找其中的键值对

4 个答案: