用
Stringsif (s.contains("a")||s.contains("b")||s.contains("c"))
这是一个几乎相同但更具可扩展性的 LINQ 解决方案：
new[] { "a", "b", "c" }.Any(c => s.Contains(c))
好吧，总是有这样的：
public static bool ContainsAny(this string haystack, params string[] needles)
{
foreach (string needle in needles)
{
if (haystack.Contains(needle))
return true;
}
return false;
}
用途：
bool anyLuck = s.ContainsAny("a", "b", "c");
但是，没有什么可以与您的
||var values = new [] {"abc", "def", "ghj"};
var str = "abcedasdkljre";
values.Any(str.Contains);
你可以尝试使用正则表达式
string s;
Regex r = new Regex ("a|b|c");
bool containsAny = r.IsMatch (s);
如果您需要具有特定
StringComparisonpublic static class StringExtensions
{
public static bool ContainsAny(this string input, IEnumerable<string> containsKeywords, StringComparison comparisonType)
{
return containsKeywords.Any(keyword => input.IndexOf(keyword, comparisonType) >= 0);
}
}
与
StringComparison.CurrentCultureIgnoreCasevar input = "My STRING contains Many Substrings";
var substrings = new[] {"string", "many substrings", "not containing this string" };
input.ContainsAny(substrings, StringComparison.CurrentCultureIgnoreCase);
// The statement above returns true.
”xyz”.ContainsAny(substrings, StringComparison.CurrentCultureIgnoreCase);
// This statement returns false.
这是一个“更好的解决方案”并且非常简单
if(new string[] { "A", "B", ... }.Any(s=>myString.Contains(s)))
List<string> includedWords = new List<string>() { "a", "b", "c" };
bool string_contains_words = includedWords.Exists(o => s.Contains(o));
public static bool ContainsAny(this string haystack, IEnumerable<string> needles)
{
return needles.Any(haystack.Contains);
}
由于字符串是字符的集合，因此您可以对它们使用 LINQ 扩展方法：
if (s.Any(c => c == 'a' || c == 'b' || c == 'c')) ...
这将扫描字符串一次并在第一次出现时停止，而不是为每个字符扫描一次字符串直到找到匹配项。
这也可以用于您喜欢的任何表达式，例如检查字符范围：
if (s.Any(c => c >= 'a' && c <= 'c')) ...
// Nice method's name, @Dan Tao
public static bool ContainsAny(this string value, params string[] params)
{
return params.Any(p => value.Compare(p) > 0);
// or
return params.Any(p => value.Contains(p));
}
AnyAll static void Main(string[] args)
{
string illegalCharacters = "!@#$%^&*()\\/{}|<>,.~`?"; //We'll call these the bad guys
string goodUserName = "John Wesson"; //This is a good guy. We know it. We can see it!
//But what if we want the program to make sure?
string badUserName = "*_Wesson*_John!?"; //We can see this has one of the bad guys. Underscores not restricted.
Console.WriteLine("goodUserName " + goodUserName +
(!HasWantedCharacters(goodUserName, illegalCharacters) ?
" contains no illegal characters and is valid" : //This line is the expected result
" contains one or more illegal characters and is invalid"));
string captured = "";
Console.WriteLine("badUserName " + badUserName +
(!HasWantedCharacters(badUserName, illegalCharacters, out captured) ?
" contains no illegal characters and is valid" :
//We can expect this line to print and show us the bad ones
" is invalid and contains the following illegal characters: " + captured));
}
//Takes a string to check for the presence of one or more of the wanted characters within a string
//As soon as one of the wanted characters is encountered, return true
//This is useful if a character is required, but NOT if a specific frequency is needed
//ie. you wouldn't use this to validate an email address
//but could use it to make sure a username is only alphanumeric
static bool HasWantedCharacters(string source, string wantedCharacters)
{
foreach(char s in source) //One by one, loop through the characters in source
{
foreach(char c in wantedCharacters) //One by one, loop through the wanted characters
{
if (c == s) //Is the current illegalChar here in the string?
return true;
}
}
return false;
}
//Overloaded version of HasWantedCharacters
//Checks to see if any one of the wantedCharacters is contained within the source string
//string source ~ String to test
//string wantedCharacters ~ string of characters to check for
static bool HasWantedCharacters(string source, string wantedCharacters, out string capturedCharacters)
{
capturedCharacters = ""; //Haven't found any wanted characters yet
foreach(char s in source)
{
foreach(char c in wantedCharacters) //Is the current illegalChar here in the string?
{
if(c == s)
{
if(!capturedCharacters.Contains(c.ToString()))
capturedCharacters += c.ToString(); //Send these characters to whoever's asking
}
}
}
if (capturedCharacters.Length > 0)
return true;
else
return false;
}
您可以为您的扩展方法创建一个类并添加这个：
public static bool Contains<T>(this string s, List<T> list)
{
foreach (char c in s)
{
foreach (T value in list)
{
if (c == Convert.ToChar(value))
return true;
}
}
return false;
}
在 .NET 8+ 中，有一种新的更快的方法来搜索字符串中的字符。新类称为
SearchValues<T>using System.Buffers;
public class TestClass
{
// A fixed set of characters. Works in .NET 8.
private static readonly SearchValues<char> searchValues = SearchValues.Create([ 'a', 'b', 'c' ]);
// A fixed set of strings. Works in .NET 9.
// private static readonly SearchValues<string> searchValues2 = SearchValues.Create([ "Hi", "Hello" ], StringComparison.OrdinalIgnoreCase);
static void Main(string[] args)
{
string text = "Hi friend";
// In .NET 8.
Console.WriteLine(text.AsSpan().ContainsAny(searchValues));
// In .NET 9.
// Console.WriteLine(text.AsSpan().ContainsAny(searchValues2));
}
}
https://github.com/dotnet/runtime/pull/78093 显示了使用
SearchValuesIndexOfAnyValues您可以使用正则表达式
if(System.Text.RegularExpressions.IsMatch("a|b|c"))
如果这是有要求的密码检查器，请尝试以下操作：
public static bool PasswordChecker(string input)
{
// determins if a password is save enough
if (input.Length < 8)
return false;
if (!new string[] { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R",
"S", "T", "U", "V", "W", "X", "Y", "Z", "Ä", "Ü", "Ö"}.Any(s => input.Contains(s)))
return false;
if (!new string[] { "1", "2", "3", "4", "5", "6", "7", "8", "9", "0"}.Any(s => input.Contains(s)))
return false;
if (!new string[] { "!", "'", "§", "$", "%", "&", "/", "(", ")", "=", "?", "*", "#", "+", "-", "_", ".",
",", ";", ":", "`", "´", "^", "°", }.Any(s => input.Contains(s)))
return false;
return true;
}
这会将密码设置为最小长度为 8，并使用至少一个大写字符、至少一个数字和至少一个特殊字符