iphone - 如何从 NSString 获取整数的数字？

Question

我有一个类似的字符串NSString *str = @"123"。我想将此字符串的数字填充到 UIPickerView。但是如何从该字符串中获取数字？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

请看这个。。

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，其他解决方案似乎是多余的。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，你可以这样做

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

数组中的每个元素都是一个 NSString 形式的数字。

Answer 4

未经测试，但你可以试一试，这应该扫描你的字符串的所有数字条目。

-(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

另一个答案通过解决将 int 分成数字的问题来解决原始问题的更多想法：

  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--;
  }