NSString by removing the initial zeros? - objective-c

Question

How can I remove leading zeros from an NSString?
e.g. I have:
NSString *myString;
with values such as #"0002060", #"00236" and #"21456".
I want to remove any leading zeros if they occur:
e.g. Convert the previous to #"2060", #"236" and #"21456".
Thanks.

Answer 1

For smaller numbers:
NSString *str = #"000123";
NSString *clean = [NSString stringWithFormat:#"%d", [str intValue]];
For numbers exceeding int32 range:
NSString *str = #"100004378121454";
NSString *clean = [NSString stringWithFormat:#"%d", [str longLongValue]];

Answer 2

This is actually a case that is perfectly suited for regular expressions:
NSString *str = #"00000123";
NSString *cleaned = [str stringByReplacingOccurrencesOfString:#"^0+"
withString:#""
options:NSRegularExpressionSearch
range:NSMakeRange(0, str.length)];
Only one line of code (in a logical sense, line breaks added for clarity) and there are no limits on the number of characters it handles.
A brief explanation of the regular expression pattern:
The ^ means that the pattern should be anchored to the beginning of the string. We need that to ensure it doesn't match legitimate zeroes inside the sequence of digits.
The 0+ part means that it should match one or more zeroes.
Put together, it matches a sequence of one or more zeroes at the beginning of the string, then replaces that with an empty string - i.e., it deletes the leading zeroes.

Answer 3

The following method also gives the output.
NSString *test = #"0005603235644056";
// Skip leading zeros
NSScanner *scanner = [NSScanner scannerWithString:test];
NSCharacterSet *zeros = [NSCharacterSet
characterSetWithCharactersInString:#"0"];
[scanner scanCharactersFromSet:zeros intoString:NULL];
// Get the rest of the string and log it
NSString *result = [test substringFromIndex:[scanner scanLocation]];
NSLog(#"%# reduced to %#", test, result);

Answer 4

- (NSString *) removeLeadingZeros:(NSString *)Instring
{
NSString *str2 =Instring ;
for (int index=0; index<[str2 length]; index++)
{
if([str2 hasPrefix:#"0"])
str2 =[str2 substringFromIndex:1];
else
break;
}
return str2;
}

Answer 5

In addition to adali's answer, you can do the following if you're worried about the string being too long (i.e. greater than 9 characters):
NSString *str = #"000200001111111";
NSString *strippedStr = [NSString stringWithFormat:#"%lld", [temp longLongValue]];
This will give you the result: 200001111111
Otherwise, [NSString stringWithFormat:#"%d", [temp intValue]] will probably return 2147483647 because of overflow.