如何从NSString中获取整数的位数

Question

我有一个类似NSString *str = @"123"的字符串。我想把这个字符串的数字填充到UIPickerView中。但是如何从这个字符串中获取数字呢？我添加了以下代码

- (void)pickerView:(UIPickerView *)pickerView didSelectRow: (NSInteger)row inComponent:(NSInteger)component 
{
 int number = [str intValue];
 if(component == 0)
 {
 }
 else if(component == 1)
 {
 }
 else 
 {
 }
}

Answer 1

请查看。。

NSMutableArray *arrNumbers = [[NSMutableArray] alloc] initWithCapacity:[YOURSTRING length]];
for (i=0;i<[YOURSTRING length];i++) 
{
  unichaar ch = [YOURSTRING characterAtIndex:i];
  NSLog(@"Processing charachter %c",ch);
  // If you really want
  [arrNumbers addObject:(id)ch];
}

Answer 2

考虑到NSString已经是一个字符数组，其他解决方案似乎太多了。更轻量级的解决方案：

NSString *str = @"123";
for (int i = 0; i < [str length]; i++) {
    int digit = [str characterAtIndex:i] - '0';
    // do something with your digit
}

Answer 3

如果你把它作为一个字符串，你就可以进行

NSArray * digitStrings = [str componentsSeparatedByString:""];

数组中的每个元素都是一个数字，作为一个NSString。

Answer 4

未测试，但您可以尝试一下，这应该扫描字符串中的所有数字项。

-(NSArray*)getDigitsFromString:(NSString*)str{
NSMutableString *outpuString = [NSMutableString
                                stringWithCapacity:str.length];
NSScanner *scanner = [NSScanner scannerWithString:str];
NSCharacterSet *numbers = [NSCharacterSet
                           characterSetWithCharactersInString:@"0123456789"];
while ([scanner isAtEnd] == NO) {
    NSString *buffer;
    if ([scanner scanCharactersFromSet:numbers intoString:&buffer]) {
        [outpuString appendString:buffer];
    } else {
        [scanner setScanLocation:([scanner scanLocation] + 1)];
    }
}
NSArray * digitStr = [outpuString componentsSeparatedByString:@""];
    return digitStr;
}

Answer 5

 NSMutableArray * digit=[[NSMutableArray alloc]init];
    NSString *string = @"123456";
    for (int i=0;i<[string length]; i++) {
        NSString * newString = [string substringWithRange:NSMakeRange(i, 1)];
        [digit addObject:newString];
    }
    NSLog(@"String %@ ", digit)

Answer 6

还有一个答案，它通过解决将int分隔成数字的问题，更多地解决了原始问题的想法：

  NSString *numberString = @"68243";
  int result[numberString.length]; 
  NSInteger number = [numberString integerValue];
  int j = numberString.length - 1;
  while (j >= 0) 
  {
    int power = pow(10, j);
    int rest = (number %  power);
    result[j] = (number - rest)/power;
    number = rest;
    j--;
  }