c# - 在c#中搜索一些字符串

Question

如何在 C# 中搜索一些字符串？好吧，如果我有字符串“詹姆斯邦德”并且我正在搜索“詹姆斯”或“詹姆斯”，它将返回真，但如果我正在搜索“詹姆斯”，它将返回假。我怎么能这样做？也许我需要一点具体。我需要根据以“”分隔的单词进行搜索，请参见上文。如果我正在搜索 jame，它将返回 false。如果我在搜索 jame 时使用 contains，它也会返回 true 对吗？

Answer 1

You will have to use Regex for this. You cannot use Contains, since it won't take into consideration case-insensitivity and match whole word pattern. Use this instead:

string text = "James bond";

// this will return true  
bool result = Regex.IsMatch(text, "\\bjames\\b", RegexOptions.IgnoreCase);

// this will return false   
bool result = Regex.IsMatch(text, "\\bjame\\b", RegexOptions.IgnoreCase);

In the Regex formats, the above \bs will match an alphanumeric-to-nonalphanumeric boundary (or vice-versa). In this case, this ensures that you will be matching james or jame as a whole word and not a partial word.

Answer 2

As per your question this is what you would use.

    var ex = "James Bond".ToLower(); //normalize case
    bool contains = ex.Split(' ').Any( x => x == "jame");
   //FALSE because the *word* "jame" is not found in "james bond"

Since this question is causing a lot of confusion, you have to keep in mind all of the casing involved.

var ex = "James Bond";
bool contains = ex.Contains("jame");
// FALSE because "jame" is not found in "James Bond" due to case-sensitivity

var ex = "James Bond".ToLower(); //normalize case
bool contains = ex.Contains("jame");
// TRUE because "jame" is FOUND in "james bond" due to normalized case

Answer 3

You can use Split to separate a string into parts that are separated. Ex:

string[] items = "James Bond".Split(' ');
// items == { "James", "Bond" }

You can use ToLower to prevent case senstivity. Ex:

string lower = "James Bond".ToLower();
// lower == "james bond"

You can use StartsWith to determine if a string starts with some substring. Ex:

bool startsWithJame = "James Bond".StartsWith("Jame");
// startsWithJame == true

Using them all together:

bool anyWordStartsWith_jame_NoCaseSensitivity =
   "James Bond"
   .ToLower()
   .Split(' ')
   .Any(str => str.StartsWith("jame"));
// anyWordStartsWith_jame_NoCaseSensitivity == true

Answer 4

使用正则表达式。有关示例，请参见：

http://msdn.microsoft.com/en-us/library/ms228595%28v=vs.80%29.aspx

当在字符串中的任何位置找到“cow”时，这里是匹配的。在您的情况下，它将是“Jame”。

Answer 5

您可以使用Contains方法搜索：

string[] names = new string[] { "joe", "bob", "chris" };
if(names.Contains("james")){
    //code
}

Answer 6

您可以使用正则表达式使用单词边界来做到这一点。以下代码将向您展示如何使用不区分大小写的搜索进行匹配，并且不会出现“jame”之类的误报。它适用于给定字符串中的任何位置。

    static void Main(string[] args)
    {
        string name_to_match = "James Bond";
        string word_to_find = "james";
        string word_to_not_find = "jame";

        string patternToFind = string.Format(@"\b{0}\b", word_to_find);
        string patternToNotFind = string.Format(@"\b{0}\b", word_to_not_find);

        Regex regexToFind = new Regex(patternToFind, RegexOptions.IgnoreCase);
        Regex regexToNotFind = new Regex(patternToNotFind, RegexOptions.IgnoreCase);

        bool foundNameExpected = regexToFind.IsMatch(name_to_match);
        bool foundNameNotExpected = regexToNotFind.IsMatch(name_to_match);
    }

在这种情况下，布尔值 foundNameExpected 将为真（因为我们希望 "james" 匹配 "James Bond" 中的 "James"），但 foundNameNotExpected 将为假（因为我们不希望 "jame" 匹配 "James"）。

Answer 7

试试这个。

方法：1

string s1 = "The quick brown fox jumps over the lazy dog";
string s2 = "fox";
bool b;
bool c;
b = s1.Contains(s2);
c = s1.Contains("test")

bool b 将返回 true。
bool c 将返回 false。

方法：2

    string str = "My Name is james";  

 int result = str.IndexOf("james"); 

如果在句子中找不到特定的单词，结果将为 -1。