objective-c Padding string to left
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Padding string to left
提问by TonyNeallon
How can one pad a string to left in objective c. E.g if I have an integer value of 6 I want it to be displayed as 06.
How can one pad a string to left in objective c. E.g if I have an integer value of 6 I want it to be displayed as 06.
I use stringByPaddingToLength:but it pads it to the right like 60.
I use stringByPaddingToLength:but it pads it to the right like 60.
Your help is much appreciated.
Your help is much appreciated.
采纳答案by aimless
+ (NSString *)formatValue:(int)value forDigits:(int)zeros {
NSString *format = [NSString stringWithFormat:@"%%0%dd", zeros];
return [NSString stringWithFormat:format,value];
}
回答by nevan king
This one pads left with 10 zeroes.
This one pads left with 10 zeroes.
NSString *padded = [NSString stringWithFormat:@"Padded left with zeros: %010d", 65];
回答by dreamlax
Clumsy, but it'll do the job.
Clumsy, but it'll do the job.
@implementation NSString (LeftPadding)
- (NSString *)stringByPaddingTheLeftToLength:(NSUInteger)newLength withString:(NSString *)padString startingAtIndex:(NSUInteger)padIndex
{
if ([self length] <= newLength)
return [[@"" stringByPaddingToLength:newLength - [self length] withString:padString startingAtIndex:padIndex] stringByAppendingString:self];
else
return [[self copy] autorelease];
}
@end
Then you can do:
Then you can do:
NSString *test1 = [@"6" stringByPaddingTheLeftToLength:10 withString:@"0" startingAtIndex:0];
// test1 = "0000000006"
NSString *test2 = [@"asdf" stringByPaddingTheLeftToLength:10 withString:@"qwer" startingAtIndex:0];
// test2 = "qwerqwasdf"
NSString *test3 = [@"More than ten characters" stringByPaddingTheLeftToLength:10 withString:@"bamboo" startingAtIndex:0];
// test3 = "More than ten characters"
NSString *test4 = [test3 stringByPaddingTheLeftToLength:100 withString:test2 startingAtIndex:0];
// test4 = "qwerqwasdfqwerqwasdfqwerqwasdf...qwerqMore than ten characters"
回答by bmauter
Old thread, I know, but this is a handy way to left pad. I have it my Util class. You can adapt it to right pad if needed. The best part is that it works with whatever padding you want.
Old thread, I know, but this is a handy way to left pad. I have it my Util class. You can adapt it to right pad if needed. The best part is that it works with whatever padding you want.
+ (NSString *) leftPadString:(NSString *)s withPadding:(NSString *)padding {
NSString *padded = [padding stringByAppendingString:s];
return [padded substringFromIndex:[padded length] - [padding length]];
}
ARC and non-ARC compliant. :)
ARC and non-ARC compliant. :)
To call it, use [Util leftPadString:@"42" withPadding:@"0000"];.
To call it, use [Util leftPadString:@"42" withPadding:@"0000"];.
You could also put it in a category on NSString for an even easier call like [@"42" stringByLeftPadding:@"0000"].
You could also put it in a category on NSString for an even easier call like [@"42" stringByLeftPadding:@"0000"].
Both give you 0042.
Both give you 0042.
回答by BananaAcid
for completness (using *placeholder):
for completness (using *placeholder):
NSString *paddedNumberString = [NSString stringWithFormat:@"%0*d", amountOfZeros, numberNSInteger]
