NSString stringWithFormat problem

Question

I have such a problem: double calcValue;

NSString *buf = [NSString stringWithFormat:@"%14f", myCalculator.calcValue];

buf = "7.142857";

istead of

buf = "7.1428571428571423";

I tried to format it in such ways: @"%f". But when I tried @"%14.9f" 9 signs after comma displayed.

Whats the problem? And how can I solve it? Thanx!

Joshua Weinberg · Accepted Answer · 2010-11-08 18:31:45Z

3

Unless I'm misunderstanding, the correct format would be @"%.14f.

What you did, @"%14f" says you want up to 14 digits, before the decimal, but you didn't specify digits after.

answered Nov 8, 2010 at 18:31

Joshua Weinberg

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Comments

Nick Moore · Accepted Answer · 2010-11-08 10:47:40Z

1

I'm not sure why, but stringWithFormat: doesn't seem to format doubles properly. You might try this approach:

double calcValue=7.1428571428571423;
NSString *buf=[[NSNumber numberWithDouble:calcValue] stringValue];

which will set buf to @"7.142857142857142".

For tighter control over number of digits, you could use a NSNumberFormatter.

answered Nov 8, 2010 at 10:47

Nick Moore

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the answer is using "%g". it do all things together!