Objective-C中是否有与Swift中的"String(_ v: T，radix: Int，uppercase: Bool = default)“具有相同功能的方法？

Question

我刚刚找到了一个二进制版本的NSString to Print in in binary format，但我想知道是否有一个灵活的版本。

let initialBits: UInt8 = 0b00001111
let invertedBits = ~initialBits // equals 11110000
let stringOfInvertedBits = String(invertedBits, radix: 2) // convert to string in binary
print(stringOfInvertedBits) // 11110000

radix: 2表示二进制，radix: 8表示八进制，依此类推...

Answer 1

这是@Paul Griffiths答案的修改，它更快更有效，因为它避免了不断地重新分配NSString

- (NSString *)formatStringFromInt:(int)value withRadix:(int)radix
{
    if (value == 0)
        return @"0";
    if (radix < 2 || radix > 36)
        radix = 10;

    const unsigned buffsize = 64;
    unichar buffer[buffsize];
    unsigned offset = buffsize;
    static const char digits[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    int absValue = abs(value);
    while (absValue > 0) {
        buffer[--offset] = (unichar)digits[absValue % radix];
        absValue /= radix;
    }

    if (value < 0)
        buffer[--offset] = '-';

    return [[NSString alloc] initWithCharacters:buffer + offset
                                         length:buffsize - offset];
}

产生：

2016-01-08 11:52:53.644 stringformatprefix[7560:606490] D
2016-01-08 11:52:53.645 stringformatprefix[7560:606490] 13
2016-01-08 11:52:53.645 stringformatprefix[7560:606490] -15
2016-01-08 11:52:53.645 stringformatprefix[7560:606490] -23
2016-01-08 11:52:53.645 stringformatprefix[7560:606490] 1101

Answer 2

下面是一个简单的修改：

#import <Foundation/Foundation.h>

NSString * getBitStringForInt(const int value, const int radix) {
    static const char digits[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    if ( radix < 2 || radix > 36 ) {
        return NULL;
    }

    NSString *bits = @"";
    int absValue = abs(value);

    while ( absValue ) {
        bits = [NSString stringWithFormat:@"%c%@", digits[absValue % radix], bits];
        absValue /= radix;
    }

    if ( value < 0 ) {
        bits = [NSString stringWithFormat:@"-%@", bits];
    }

    return bits;
}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSString * val = getBitStringForInt(13, 16);
        NSLog(@"%@", val);

        val = getBitStringForInt(13, 10);
        NSLog(@"%@", val);

        val = getBitStringForInt(-13, 8);
        NSLog(@"%@", val);

        val = getBitStringForInt(-13, 5);
        NSLog(@"%@", val);

        val = getBitStringForInt(13, 2);
        NSLog(@"%@", val);
    }
    return 0;
}

带输出：

2016-01-07 21:59:59.144 TestCmdLine[49904:18135090] D
2016-01-07 21:59:59.145 TestCmdLine[49904:18135090] 13
2016-01-07 21:59:59.145 TestCmdLine[49904:18135090] -15
2016-01-07 21:59:59.145 TestCmdLine[49904:18135090] -23
2016-01-07 21:59:59.145 TestCmdLine[49904:18135090] 1101
Program ended with exit code: 0