Objective-C removing whitespace from strings in array

I want to import a file of strings line by line into an array. I want to get rid of all of the whitespace before and after the strings so that I can compare the strings a lot easier without having them not match due to small whitespace discrepancies. I NSData the content of the files then take the two strings

NSString* string  = [[[NSStri开发者_JAVA技巧ng alloc] initWithBytes:[data bytes]
                                                  length:[data length] 
                                                encoding:NSUTF8StringEncoding] autorelease];

NSString* string2  = [[[NSString alloc] initWithBytes:[data2 bytes]
                                                   length:[data2 length] 
                                                 encoding:NSUTF8StringEncoding] autorelease];

I tried below to remove the whitespace before adding to an array but it does not seem to work.

NSString *newString = [string stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceCharacterSet]];
NSString *newString2 = [string2 stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceCharacterSet]];

NSArray *fileInput = [newString componentsSeparatedByString:@"\n"];
NSArray *fileInput2 = [newString2 componentsSeparatedByString:@"\n"];

If you are looking at substituting all occurrences of whitespace then using stringByTrimmingCharactersInSet: won't help as it only trims off at the start and end of the string. You will need to use the stringByReplacingOccurrencesOfString:withString: method to eliminate the whitespace.

NSString * newString = [string stringByReplacingOccurrencesOfString:@" " withString:@""];
NSString * newString2 = [string2 stringByReplacingOccurrencesOfString:@" " withString:@""];

However,

If you want to trim all the strings in the array then you will have to enumerate the array and add the trimmed strings in a new mutable array.

Looks to me like you are removing the white space from the front and back of the whole file but not from each line. Try something like this;

NSArray *fileInput2 = [newString2 componentsSeparatedByString:@"\n"];
NSMutableArray *trimmedFileInput2 = [NSMutableArray array];
for(NSString *gak in fileInput2) {
    [trimmedFileInput2 addObject:[gak stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
}

[Thanks @Deepak for the comment, dooh!]

Both @Deepak and @Bill Dudney being right, I'm just throwing in another way to solve your problem:

NSMutableArray *fileInput = [NSMutableArray array];

[string enumerateLinesUsingBlock:^(NSString *line, BOOL *stop) {
    if ([line length] > 0) {
        [fileInput addObject:
            [line stringByTrimmingCharactersInSet:
                [NSCharacterSet whitespaceCharacterSet]];
    }
}];

(Disclaimer: Works in iOS 4+, OS X 10.6+ only... but I love blocks! :))