Objective-C 中的字符串操作

Objective-C 是一种面向对象的编程语言，用于开发iOS和Mac应用程序。在Objective-C中，字符串操作是非常常见的任务之一。字符串操作包括创建、连接、截取和比较字符串。本文将介绍Objective-C中的字符串操作，并提供一些案例代码帮助读者更好地理解。

objective-c
NSString *str1 = @"Hello World"; // 直接赋值
NSString *str2 = [NSString stringWithFormat:@"The answer is %d", 42]; // 格式化字符串

objective-c
NSString *str1 = @"Hello";
NSString *str2 = @"World";
NSString *result = [str1 stringByAppendingString:str2];
NSLog(@"%@", result); // 输出 "HelloWorld"

objective-c
NSString *str = @"Hello World";
NSString *substring = [str substringWithRange:NSMakeRange(6, 5)];
NSLog(@"%@", substring); // 输出 "World"

objective-c
NSString *str1 = @"Hello";
NSString *str2 = @"World";
if ([str1 isEqualToString:str2]) {
    NSLog(@"两个字符串相等");
} else {
    NSLog(@"两个字符串不相等");
}

objective-c
NSString *str = @"Hello World";
NSString *newStr = [str stringByReplacingOccurrencesOfString:@"World" withString:@"Objective-C"];
NSLog(@"%@", newStr); // 输出 "Hello Objective-C"

objective-c
NSString *str = @"Hello World";
NSUInteger length = [str length];
NSLog(@"字符串的长度为：%lu", length); // 输出 "字符串的长度为：11"

objective-c
NSString *str = @"Hello World";
if ([str rangeOfString:@"World"].location != NSNotFound) {
    NSLog(@"字符串包含子串");
} else {
    NSLog(@"字符串不包含子串");
}

objective-c
NSString *str = @"Hello World";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"[A-Z]" options:0 error:nil];
NSArray *matches = [regex matchesInString:str options:0 range:NSMakeRange(0, [str length])];
for (NSTextCheckingResult *match in matches) {
    NSLog(@"%@", [str substringWithRange:match.range]);
}