ios - 字符串操作：更高级的子字符串

Question

您将如何从下面的长字符串中提取“19”？这就是我的做法，但我想知道，有没有比这更好/更快的方法？

NSString *myString = @"13.5 Points-(19) 38 Points-(50) 50 Points-(215) 4.3 Points-105.8 Points-21";
NSArray  *myArray  = [myString componentsSeparatedByString:@"-"];

NSString *splitString  = [myArray        objectAtIndex:1             ];
NSRange  range         = [splitString    rangeOfString:@")"          ];
NSString *newString    = [splitString substringToIndex:range.location];

NSString *newString2 = [newString stringByReplacingOccurrencesOfString:@"(" withString:@""];

NSLog(@"newString2: %@", newString2);

Answer 1

componentsSeparatedByString当您只需要一小段原始字符串时，使用效率非常低。您不必要地解析整个字符串。

解决方案实际上取决于字符串的格式。如果您想要始终位于第一对括号中的子字符串，那么使用rangeOfString获取 first(和 first会更有效)。然后你提取两者之间的部分。

示例（没有任何适当的错误检查）：

NSString *myString = @"13.5 Points-(19) 38 Points-(50) 50 Points-(215) 4.3 Points-105.8 Points-21";
NSRange openRange = [myString rangeOfString:@"("];
NSRange closeRange = [myString rangeOfString:@")"];

NSRange resultRange = NSMakeRange(openRange.location + 1, closeRange.location - openRange.location - 1);
NSString *result = [myString substringWithRange:resultRange];

Answer 2

试试这个

NSString *myString = @"13.5 Points-(19) 38 Points-(50) 50 Points-(215) 4.3 Points-105.8 Points-21";
NSArray *strArr = [myString componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString: @"()"]];

NSLog(@"myString..%@",[strArr objectAtIndex:1]);// myString..19