Five ways to use C# to determine whether a string contains uppercase characters

This article provides five methods to determine whether a string contains capital characters and its implementation source code for your implementation reference.

Method 1: First determine whether the string is empty, and then determine whether it is a capital letter by character.

bool hasUpperCase (string str) {
    if((str))
         return false;
    for (int i = 0; i < ; i++) {
        if ( (str[i]))
            return true;                    
    }
    return false;
}

Method 2: Any method using strings

bool HasUpperCase (string str) {
    return !(str) && (c => (c));
}

Method 3: Convert to uppercase and compare whether it is equal

bool hasUpperCase (string str) {
 if((str))
     return false;
 
  return str != ();
}

Method 4: Regular matching method to determine whether characters containing A~Z

bool testCaseTwo(string str)
{
    bool result = false;
    if ((str))
    {
            return false;
    }
    result = (str, "\"[A-Z]\"");
    return result;
}
// Compact versionbool hasUpperCase(string str) {
    if ((str))
        return false;
    return (str, "\"[A-Z]\"");
}

Method 5: Make judgments based on the ASCII code to determine whether the ASCII code of the character is between 64 and 91

    static bool testCaseFour(string str)
    {
        bool result = false;
 
        if ((str))
        {
            return false;
        }
        for (int i = 0; i < ; i++)
        {
 
            if (str[i] > 64 && str[i] < 91)
            {
                result = true;
                break;
            }
        }
 
        return result;
    }

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