使用逗號分隔格式化包含數字的字符串

Question

我有一個存儲在NSMutableString實例中的號碼，我想用逗號分隔符自動格式化，然後在UITextField中顯示結果。

我試過使用NSNumberFormatter格式化爲貨幣，但我不希望它顯示小數，如果原始NSMutableString不包含小數位。

例如：

• 如果NSMutableString包含 「1234567」，應該爲 「1,234,567」 的格式。
• 如果NSMutableString包含「1234567.1」，應該爲「1,234,567.1」
• 如果NSMutableString包含「1234567.12」格式，它應該爲「1,234,567.12」

的NSMutableString將包含最大小數格式化是2.

任何幫助，非常感謝。

謝謝！

Answer 1

請記住，你真的應該本地化這個，如果你對這個用戶進行交互，但是這裏是做這件事：

- (NSString *)formatString:(NSString *)string { 
    // Strip out the commas that may already be here: 
    NSString *newString = [string stringByReplacingOccurrencesOfString:@"," withString:@""]; 
    if ([newString length] == 0) { 
     return nil; 
    } 

    // Check for illegal characters 
    NSCharacterSet *disallowedCharacters = [[NSCharacterSet characterSetWithCharactersInString:@"."] invertedSet]; 
    NSRange charRange = [newString rangeOfCharacterFromSet:disallowedCharacters]; 
    if (charRange.location != NSNotFound) { 
     return nil; 
    } 

    // Split the string into the integer and decimal portions 
    NSArray *numberArray = [newString componentsSeparatedByString:@"."]; 
    if ([numberArray count] > 2) { 
     // There is more than one decimal point 
     return nil; 
    } 

    // Get the integer 
    NSString *integer   = [numberArray objectAtIndex:0]; 
    NSUInteger integerDigits = [integer length]; 
    if (integerDigits == 0) { 
     return nil; 
    } 

    // Format the integer. 
    // You can do this by first converting to a number and then back to a string, 
    // but I would rather keep it as a string instead of doing the double conversion. 
    // If performance is critical, I would convert this to a C string to do the formatting. 
    NSMutableString *formattedString = [[NSMutableString alloc] init]; 
    if (integerDigits < 4) { 
     [formattedString appendString:integer]; 
    } else { 
     // integer is 4 or more digits 
     NSUInteger startingDigits = integerDigits % 3; 
     if (startingDigits == 0) { 
      startingDigits = 3; 
     } 
     [formattedString setString:[integer substringToIndex:startingDigits]]; 
     for (NSUInteger index = startingDigits; index < integerDigits; index = index + 3) { 
      [formattedString appendFormat:@",%@", [integer substringWithRange:NSMakeRange(index, 3)]]; 
     } 
    } 

    // Add the decimal portion if there 
    if ([numberArray count] == 2) { 
     [formattedString appendString:@"."]; 
     NSString *decimal = [numberArray objectAtIndex:1]; 
     if ([decimal length] > 0) { 
      [formattedString appendString:decimal]; 
     } 
    } 

    return formattedString; 
} 

// Test cases: 
NSLog(@"%@", [self formatString:@"123456"]); 
NSLog(@"%@", [self formatString:@"1234567."]); 
NSLog(@"%@", [self formatString:@"12345678.1"]); 
NSLog(@"%@", [self formatString:@"123456789.12"]); 

// Output: 
123,456 
1,234,567. 
12,345,678.1 
123,456,789.12 

Answer 2

您正在尋找有關NSNumberFormatter的-setMinimumFractionDigits:方法。將其設置爲0，如果有任何要放在它後面，它只會顯示小數點。

Answer 3

我想這應該做到這一點 - 我說的，如果檢查語句是否有在值輸入小數點。本例中的「輸出」是一個屬性，我已綁定到文本字段的值以顯示結果。

-(IBAction)doConversion:(id)sender{ 
    NSNumberFormatter *formatter = [[NSNumberFormatter alloc]init]; 
    [formatter setMaximumFractionDigits:2]; 
    [formatter setUsesGroupingSeparator:YES]; 
    [formatter setNumberStyle:NSNumberFormatterDecimalStyle]; 

    double entryFieldFloat = [entryField doubleValue]; 
    if ([entryField.stringValue rangeOfString:@"."].length == 1) { 
     formatter.alwaysShowsDecimalSeparator = YES; 
     self.output =[formatter stringFromNumber:[NSNumber numberWithDouble:entryFieldFloat]]; 
    }else{ 
     formatter.alwaysShowsDecimalSeparator = NO; 
     self.output =[formatter stringFromNumber:[NSNumber numberWithDouble:entryFieldFloat]]; 
    } 
} 

Answer 4

只是調用這個方法很簡單：

public static String GetCommaSeparatedCount(this Int32 Count) 
    { 
     // Check for The less-than character (<) is converted to &lt; 
     String result = String.Format("{0:#,##0}", Count); 

     return result; 
    }