NSString 中的第一个字母大写

NSString 是 Objective-C 中的一个基本数据类型，用于存储和操作文本字符串。它是一个不可变的对象，意味着一旦创建就无法修改其内容。NSString 类提供了许多实用的方法，可以方便地处理字符串的各种操作。

objective-c
NSString *myString = @"Hello, World!";

objective-c
NSString *myString = @"Hello, World!";
NSUInteger length = [myString length];
NSLog(@"字符串长度：%lu", length);

objective-c
NSString *firstName = @"John";
NSString *lastName = @"Doe";
NSString *fullName = [NSString stringWithFormat:@"%@ %@", firstName, lastName];
NSLog(@"全名：%@", fullName);

objective-c
NSString *originalString = @"Hello, World!";
NSString *subString = [originalString substringWithRange:NSMakeRange(7, 5)];
NSLog(@"截取字符串：%@", subString);

objective-c
NSString *originalString = @"Hello, World!";
NSString *replacedString = [originalString stringByReplacingOccurrencesOfString:@"World" withString:@"Objective-C"];
NSLog(@"替换后的字符串：%@", replacedString);

objective-c
NSString *originalString = @"Hello, World!";
NSRange range = [originalString rangeOfString:@"World"];
if (range.location != NSNotFound) {
    NSLog(@"找到了");
} else {
    NSLog(@"未找到");
}

objective-c
NSString *originalString = @"Hello, World!";
NSString *lowercaseString = [originalString lowercaseString];
NSString *uppercaseString = [originalString uppercaseString];
NSLog(@"转换为小写：%@\n转换为大写：%@", lowercaseString, uppercaseString);

objective-c
NSString *name = @"John";
NSInteger age = 30;
NSString *formattedString = [NSString stringWithFormat:@"My name is %@ and I'm %ld years old.", name, age];
NSLog(@"格式化后的字符串：%@", formattedString);

objective-c
NSString *string1 = @"Hello";
NSString *string2 = @"hello";
NSComparisonResult result = [string1 caseInsensitiveCompare:string2];
if (result == NSOrderedSame) {
    NSLog(@"字符串相同");
} else if (result == NSOrderedAscending) {
    NSLog(@"字符串1小于字符串2");
} else if (result == NSOrderedDescending) {
    NSLog(@"字符串1大于字符串2");
}