C# 查找字符串中出现的字符串

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

比如我有这篇课文

“嘿，罗纳德和汤姆，这个周末我们去哪里？”

但是，我想找到以“@”开头的字符串。

试试这个：

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

试试这个：

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

---

您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);
}

这将产生：

@ronald
@tom

---

您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);
}

这将产生：

@ronald
@tom

---

您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);
}

---

您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);
}

---

如果您追求速度：

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

如果您想要一个班轮：

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

---

如果您追求速度，请勾选此处

：

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

如果您想要一个班轮：

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

---

检查这里

问题仍然是，如果你期待不止一场比赛，该怎么办，如示例所示-这是效率发挥作用的地方灌输问题是，如果你期待不止一场比赛，该怎么办，如示例所示-这是效率发挥作用的地方是，如果你想删除它们，我想

Regex

将是最好的选择。是的，如果你想删除它们，我想

Regex

将是最好的选择。