Question

我的问题与这个问题类似:。 • 如何获得国家测量局或国家测量局的无计划代表? 我需要具备一些精确代表国家独立网络的示意图格式,但这一数目却被转回其他地方,我可以避免。问题一是,当数字重新转化为扼杀时,在某些情形下,扼杀在科学上。

NSDecimalNumber *dn = [NSDecimalNumber decimalNumberWithString:@"0.0001"];
NSString *s = [dn stringValue]; // s will be @"1E-4"

?

I am working in a circa 2005 version of GNUstep (possibly v1.11.1 for GNUstep Base), rather than on mac or iPhone, which may account for some of the differences in behavior vs the other question I referenced. I have looked over the base library API and the documentation in my own GNUstep install, but I can t seem to find anything to help.

<EDIT 2/7/12:

The question has changed slightly, but the goal is still the same. Originally, I didn t think I was able to control the string output piece, but I can pass the value back as a string. At this point I am attempting to use a formatting string, but I still want to prevent the scientific notation from appearing.

[NSString stringWithFormat:@"%1.14g", [val doubleValue]]

我选择使用<代码>%g,因为我们要获得一定数目的重要数字。如果我使用<条码>%f,我可以将额外零打上下,但数字并不总是干净的。例如,800 000.79 似乎为800 000.78999600。

www.un.org/Depts/DGACM/index_spanish.htm 是否有办法获得一定数量的高位数(或小数位)的干净格式数字,在位数之前显示科学位数?

我也愿意接受C项建议。

Answer 1

You should check out the NSNumberFormatter

// Create formatter 
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];     
[formatter setNumberStyle:NSNumberFormatterDecimalStyle]; // adjust this
NSString *formattedOutput = [formatter stringFromNumber:yourDecimalNumber];

Answer 2

如何获得C值(双重、公开、长期等),然后把它作为Cstring或作为NSString与stringWithFormat:一起加以编排?

Answer 3

Try printing the number using NSNumberFormatter instead of the stringValue method. It has a lot more options.

(一) 假定NSNumberFormatter,可登录在GNU步上)

Answer 4

采用以下方法避免科学权宜之计。

3. 把双向改为强硬

func getStringFrom(double doubleVal: Double) -> String
{
    var stringValue : String = "0.00"

    let formatter = NSNumberFormatter()
    formatter.usesSignificantDigits = true;
    formatter.maximumSignificantDigits = 100
    formatter.groupingSeparator = "";
    formatter.numberStyle = .DecimalStyle
    stringValue = formatter.stringFromNumber(doubleVal)!;

    return stringValue

iii

争取双赢

func getDoubleFrom(textField textField: UITextField) -> Double
{
    var doubleValue : Double = 0.0

    if let val = textField.text
    {
        let numberFormatter = NSNumberFormatter()
        numberFormatter.numberStyle = NSNumberFormatterStyle.DecimalStyle
        let finalNumber = numberFormatter.numberFromString(val)
        doubleValue = (finalNumber?.doubleValue)!;
    iii

    return doubleValue
iii

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