#import "DMViewController.h"  @interface DMViewController () @property (weak, nonatomic) IBOutlet UITextField *titleText; @property (weak, nonatomic) IBOutlet UILabel *numLab; @end @implementation DMViewController - (IBAction)tapButtonAction:(id)sender {  UIButton *tempBut = (UIButton *)sender;  if (tempBut.isSelected) {  tempBut.selected = NO;  _numLab.text = @"label";  } else {  tempBut.selected = YES;  NSString *newNumber = [self separateNumberUseCommaWith:_titleText.text];  _numLab.text = newNumber;  } } // 將數字轉為每隔3位整數由逗號“,”分隔的字符串 - (NSString *)separateNumberUseCommaWith:(NSString *)number {  // 前綴  NSString *prefix = @"￥";  // 后綴  NSString *suffix = @"元";  // 分隔符  NSString *divide = @",";  NSString *integer = @"";  NSString *radixPoint = @"";  BOOL contains = NO;  if ([number containsString:@"."]) {  contains = YES;  // 若傳入浮點數，則需要將小數點后的數字分離出來  NSArray *comArray = [number componentsSeparatedByString:@"."];  integer = [comArray firstObject];  radixPoint = [comArray lastObject];  } else {  integer = number;  }  // 將整數按各個字符為一組拆分成數組  NSMutableArray *integerArray = [[NSMutableArray alloc] init];  for (int i = 0; i < integer.length; i ++) {  NSString *subString = [integer substringWithRange:NSMakeRange(i, 1)];  [integerArray addObject:subString];  }  // 將整數數組倒序每隔3個字符添加一個逗號“,”  NSString *newNumber = @"";  for (NSInteger i = 0 ; i < integerArray.count ; i ++) {  NSString *getString = @"";  NSInteger index = (integerArray.count-1) - i;  if (integerArray.count > index) {   getString = [integerArray objectAtIndex:index];  }  BOOL result = YES;  if (index == 0 && integerArray.count%3 == 0) {   result = NO;  }  if ((i+1)%3 == 0 && result) {   newNumber = [NSString stringWithFormat:@"%@%@%@",divide,getString,newNumber];  } else {   newNumber = [NSString stringWithFormat:@"%@%@",getString,newNumber];  }  }  if (contains) {  newNumber = [NSString stringWithFormat:@"%@.%@",newNumber,radixPoint];  }  if (![prefix isEqualToString:@""]) {  newNumber = [NSString stringWithFormat:@"%@%@",prefix,newNumber];  }  if (![suffix isEqualToString:@""]) {  newNumber = [NSString stringWithFormat:@"%@%@",newNumber,suffix];  }  return newNumber; } @end