如何检测字符是大写还是小写？

Let's say I extract a single character from a NSString like this:

假设我从NSString中提取单个字符,如下所示:

[@"This is my String" characterAtIndex:0]

How do I find out if the character I get is a lowercase or uppercase character?

如何确定我得到的字符是小写还是大写字母?

Thanks for any adivice!

感谢您的任何帮助!

4 个解决方案

#1

BOOL isUppercase = [[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:[s characterAtIndex:0]];

#2

unichar ch = [@"This is my String" characterAtIndex:0];

if (ch >= 'A' && ch <= 'Z') {
    // upper case
} else if (ch >= 'a' && ch <= 'z') {
   // lower case
}

Note that this works only for English alphabet.

请注意,这仅适用于英文字母。

#3

NSString *firstChar = [NSString stringWithFormat:@"%c", [@"This is my String" characterAtIndex:0]];

BOOL isUpperCase = [firstChar isEqualToString:[firstChar uppercaseString]];

Note that, if the character doesn't have uppercase/lowercase variants (like number 1, 2, etc), the isUpperCase always return YES.

请注意,如果字符没有大写/小写变体(如数字1,2等),则isUpperCase始终返回YES。

#4

-1

I don't know objective C, but you could use a regular expression. If it matches [a-z], then it's lower case. If it matches [A-Z], it's upper case.

我不知道目标C,但你可以使用正则表达式。如果它匹配[a-z],那么它是小写的。如果它与[A-Z]匹配,则为大写。

#1

BOOL isUppercase = [[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:[s characterAtIndex:0]];

#2

unichar ch = [@"This is my String" characterAtIndex:0];

if (ch >= 'A' && ch <= 'Z') {
    // upper case
} else if (ch >= 'a' && ch <= 'z') {
   // lower case
}