NSString trim \n

Question

I have number of line breaks in a string. But I only want it to be trimmed if it is found at the start of string or at the end. It is fine if it is found in between. How to do that?

possible duplicate of [Remove whitespace from string in Objective-C](http://stackoverflow.com/questions/4645649/remove-whitespace-from-string-in-objective-c) — Eimantas, Jun 27 '12 at 06:22

score 3 · Accepted Answer · edited Mar 07 '14 at 20:14

You need to use:

- (NSString *)stringByReplacingOccurrencesOfString:(NSString *)target withString:(NSString *)replacement options:(NSStringCompareOptions)options range:(NSRange)searchRange;

The target will be @"\n"

The replacement will be @""

The range will be:

NSMakeRange(0,2); // for the beginning

and

NSMakeRange(string.length-2,2); // to the end

For example -

//for the start
[yourString stringByReplacingOccurrencesOfString:@"\n" withString:@"" options:NSCaseInsensitiveSearch range:NSMakeRange(0,2)];

//for the end
[yourString stringByReplacingOccurrencesOfString:@"\n" withString:@"" options:NSCaseInsensitiveSearch range:NSMakeRange(yourString.length,2)];

You can specify a longer length to the range to be sure that it is taking the \n.

score 1 · Answer 2 · answered Jun 27 '12 at 06:14

NSString* str = @"hdskfh   dsakjfh akhf kasdhfk asdfkjash fkadshf1234        ";
NSRange rng = [str rangeOfCharacterFromSet: [NSCharacterSet characterSetWithCharactersInString: [str stringByReplacingOccurrencesOfString: @" " withString: @""]] options: NSBackwardsSearch];
str = [str substringToIndex: rng.location+1];

score 1 · Answer 3 · answered Jun 27 '12 at 06:15

Use the following code to remove the \n from start and end

NSString *str = @"\n test test \n test \n";

int firstOccurance = [str rangeOfString:@"\n"].location;
if (firstOccurance == 0) {
    str = [str substringFromIndex:1];
}

int lastOccurance = [str rangeOfString:@"\n" options:NSBackwardsSearch].location;
if (lastOccurance == str.length - 1) {
    str = [str substringToIndex:str.length - 2];
}

score 1 · Answer 4 · answered Jun 27 '12 at 06:20

1

You can try with hasPrefix and hasSuffix

for example

NSString *str = @"\n This is a \n test \n";

if ([str hasPrefix:@"\n"])
{
     //remove it
}

if ([str hasSuffix:@"\n"])
{
      //remove it
}

answered Jun 27 '12 at 06:20

Maulik

19,348
14
82
137

What if it has two new line symbols at the beginning and at the end? – Eimantas Jun 27 '12 at 06:23
change `if` to `while`: `while( [ str hasPrefix:@"\n" ] ) { str = [ str substringFromIndex:1 ] ; }` – nielsbot Jun 27 '12 at 06:26
and `while ( [ str hasSuffix:@"\n" ] ) { str = [ str substringWithRange:(NSRange){ 0, str.length - 1 } ] ; }` – nielsbot Jun 27 '12 at 06:27

score 1 · Answer 5 · answered Jun 27 '12 at 06:26

1

You can use stringByTrimmingCharactersInSet to trim whitespace from both ends of the string.

NSString* str = [myString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

answered Jun 27 '12 at 06:26

Robotnik

3,643
3
31
49

NSString trim \n

5 Answers5