CODEWITHSUNDEEP
objective-cnsstringinstance
Matt
Matt

Reputation: 2930

Remove instances of all characters except one from NSString

I have a NSString that is dynamic and changes constantly. I need to take that NSString and replace occurrences of every character in it with @"" except the string @"\n"

So if I have NSString *string = @"This is my string at 10:00PM\n I hate this string\n"; so If I remove everything except \n by replacing everything with @"" and replace the \n occurrences with 1, my new string in the end will be 11 since there are two occurrences. The string could also have any character that exists, so it needs to remove everything except \n.

How could I do this?

Upvotes: 0

Views: 210

Answers (2)

Craig Otis
Craig Otis

Reputation: 32104

If you want a more convenient, albeit slightly more memory-intensive solution:

NSUInteger numNewlines = [[string componentsSeparatedByString:@"\n"] count] - 1;
NSMutableString *ones = [[NSMutableString alloc] initWithCapacity:numNewlines];
for (int i = 0; i < numNewLines; i++) {
    [ones appendString:@"1"];
}

Upvotes: 1

Manlio
Manlio

Reputation: 10864

I think it's easier to do something like 

NSString *newString = @"";
for(int i=0;i<[string length]; i++) 
    if([string characterAtIndex:i]=='\n')
        newString = [newString stringByAppendingString:@"1"];

string = newString;

Upvotes: 0

Related Questions