截斷額外的零格式化浮動到一個NSString

Question

時

我試圖格式化一些float S作爲如下：

1.1500將顯示爲「$ 1.15」
1.1000將顯示爲「$ 1.0」
1.0000將顯示爲「$ 1.00」
1.4710將顯示爲「$ 1.471」
1.4711將顯示爲「$ 1.4711」

我試着用

NSString *answer = [NSString stringWithFormat:@"$ %.2f",myvalue]; 

Answer 1

我必須弄明白這個文檔。你可以按照下面的實現來做到這一點。

請大家看看下面的演示代碼...

NSArray * numbers = [[NSArray alloc] initWithObjects:@"1.1500",@"1.1000",@"1.0000",@"1.4710",@"1.4711",nil]; 

for (int i=0; i<[numbers count]; i++) { 
    NSArray * floatingPoint = [[numbers objectAtIndex:i] componentsSeparatedByString:@"."]; 
    NSString * lastObject = [[floatingPoint lastObject] stringByReplacingOccurrencesOfString:@"0" withString:@""]; 
    if ([lastObject length] < 2) { 
     NSLog(@"%@",[NSString stringWithFormat:@"$ %.2f",[[numbers objectAtIndex:i] floatValue]]); 
    } else { 
     NSLog(@"%@",[NSString stringWithFormat:@"$ %g",[[numbers objectAtIndex:i] floatValue]]); 
    } 
} 

感謝，

MinuMaster

Answer 2

試試這個：

NSString *answer = [NSString stringWithFormat:@"%.02f", myvalue]; 

Answer 3

閱讀format specifiers.

Answer 4

這正是NSNumberFormatters是：

float onefifteen = 1.1500; // displayed as 「$ 1.15」 
float oneten = 1.1000;  // displayed as 「$ 1.10」 
float one = 1.0000; // displayed as 「$ 1.00」 
float onefortyseventen = 1.4710; // displayed as 「$ 1.471」 
float onefortyseveneleven = 1.4711; // displayed as 「$ 1.4711」 

NSNumberFormatter * formatter = [[NSNumberFormatter alloc] init]; 
[formatter setNumberStyle:NSNumberFormatterCurrencyStyle]; 
[formatter setUsesSignificantDigits:YES]; 
// The whole number counts as the first "significant digit" 
[formatter setMinimumSignificantDigits:3]; 

NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:onefifteen]]); 
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:oneten]]); 
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:one]]); 
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:onefortyseventen]]); 
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:onefortyseveneleven]]); 

2011-12-15 19：36：52.185 S ignificantCents [49282：903] $ 1.15
2011-12-15 19：36：52.190 SignificantCents [49282：903] $ 1.10
2011-12-15 19：36：52.190 SignificantCents [49282：903] $ 1.00包裝
2011-12 -15 19：36：52.191 SignificantCents [49282：903] $ 1.471
2011-12-15 19：36：52.192 SignificantCents [49282：903] $ 1.4711