查找字符串中出现的字符串

本文关键字：字符串 查找 | 更新日期: 2023-09-27 17:53:48

在另一个字符串中查找字符串的最快和最有效的方法是什么?

例如我有这样的文本;

"嘿，@ronald和@tom这个周末我们去哪里?"

但是我想找到以"@"开头的字符串。

查找字符串中出现的字符串

可以使用正则表达式

string test = "Hey @ronald and @tom where are we going this weekend";
Regex regex = new Regex(@"@['S]+");
MatchCollection matches = regex.Matches(test);
foreach (Match match in matches)
{
    Console.WriteLine(match.Value);
}

输出:

@ronald
@tom

你需要使用正则表达式:

string data = "Hey @ronald and @tom where are we going this weekend";
var result = Regex.Matches(data, @"@'w+");
foreach (var item in result)
{
    Console.WriteLine(item);
}

试试这个:

string s = "Hey @ronald and @tom where are we going this weekend";
var list = s.Split(' ').Where(c => c.StartsWith("@"));

速度:

string source = "Hey @ronald and @tom where are we going this weekend";
int count = 0;
foreach (char c in source) 
  if (c == '@') count++;

如果你想要一行:

string source = "Hey @ronald and @tom where are we going this weekend";
var count = source.Count(c => c == '@');

检查这里如何计算字符串中字符串的出现次数?

String str = "hallo world"
int pos = str.IndexOf("wo",0)
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