在Objective-C中拆分字符串而不删除拆分字符串

Question

我正在尝试将复杂数字的字符串拆分为实数和虚数。

我试图在Internet上找到解决方案，但是我发现的所有解决方案都消除了分裂现象。

我将在示例中显示我到底想做什么：

我有一个这样的字符串：-3.5 + 6.7i

我想将字符串分成-3.5和+ 6.7i

谢谢您的帮助！！！

Answer 1

这很简单：

NSString *complexNumber = @"-3.5+6.7i";
NSArray *components = [complexNumber componentsSeparatedByString:@"+"];
NSString *realPart = components[0];
NSString *imaginaryPart = [@"+" stringByAppendingString:components[1]];

下一个问题：如何分割@"-3.5-6.7i" ？

Answer 2

试试这个功能。 尚未测试，因此可能需要进行一些调整

+ (NSMutableArray*)split:(NSString*)string on:(NSArray*)separators
{
    NSMutableArray* answer = [[NSMutableArray alloc] init];
    NSString* substring = [NSString stringWithString:string];

    //slowly shrink the string by taking off strings from the front
    while ([substring length] > 0)
    {
        int first = 0;

        //look for the separator that occurs earliest and use that for what you are
        //splitting on. There is a slight catch here. If you have separators "abc" and "bc",
        //and are looking at string "xabcd", then you will find the strings "x", "a", and
        //"bcd" since the separators share common substrings, meaning that the strings
        //returned from this function are not guaranteed to start with one of the
        //separators.
        for (int j = 0; j < [separators count]; j++)
        {
            //need to start from index 1 so that the substring found before that caused
            //the split is not found again at index 0
            NSString* toCheck = [substring substringFromIndex:1];
            int start = [substring rangeOfString:[separators objectAtIndex:j]].location;

            if (start < first)
            {
                first = start;
            }
        }

        [answer addObject:[substring substringToIndex:start]];
        substring = [substring substringFromIndex:start];
    }

    return answer;
}

Answer 3

公认的答案很糟糕，它无法处理任何明显的极端情况。 尝试这个：

NSString * input = @"-3.5+6.7i";

NSString * const floatRe = @"\\d*(?:\\.\\d*)?";
NSString * const reStr = [NSString stringWithFormat:@"([-+]?%@)([-+]%@)i", floatRe, floatRe];
NSRegularExpression * re = [NSRegularExpression regularExpressionWithPattern:reStr options:(NSRegularExpressionOptions)0 error:NULL];
NSArray * matches = [re matchesInString:input options:(NSMatchingOptions)0 range:NSMakeRange(0, input.length)];
if (matches.count != 1) {
   // Fail.
}
NSTextCheckingResult * match = matches[0];
double real = [[input substringWithRange:[match rangeAtIndex:1]] doubleValue];
double imag = [[input substringWithRange:[match rangeAtIndex:2]] doubleValue];

NSLog(@"%lf / %lf", real, imag);