NSString strip regular \\ escape characters how?

Question

I need an efficient piece of code that strips escape characters. This is regular escapes not HTML escape characters.

Example: "\"", "\\\\", "\", "\\"

I want a general algorithm to strip any kind of escape sequences.

Could use any utility like regular expression.

  (NSString*) unescape:(NSString*) string {

      ....
  }

This is the answer I wrote:

-(NSString*) unescape:(NSString*) string
{

    for(int i = 0; i < string.length; i++) {
        char a = [string characterAtIndex:i];
        if([string characterAtIndex:i] == '\\' ) {
            string = [string stringByReplacingCharactersInRange:NSMakeRange(i,1) withString:@""];
        }

    }
    return string;
}

Answer 1

Try to use below code for HTML escape

(NSString*) unescape:(NSString*) string 
{
    return [string stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}

for regular Escape

(NSString*) unescape:(NSString*) string 
{    
    return [string stringByReplacingOccurrencesOfString:@"\\\"" withString:@"\""];
}

Answer 2

The best method that you should use is:

- (NSString *)stringByTrimmingCharactersInSet:(NSCharacterSet *)set

You would call it using:

string = [string stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];

Answer 3

If you want to use regex, you can try with regex pattern \\[bntr\\\\"]. Or use any required regex pattern here.

NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:
                              @"\\[bntr\\\\"]" options:0 error:nil];

[regex replaceMatchesInString:str options:0 range:NSMakeRange(0, [str length]) withTemplate:@""];

Answer 4

I apoligize for my answer...

NSString *_string = @"\\\\ dfsdg \\ tr\\\\t \\\\\\tw\\\\\\\\w\\ t\\ \\\\ \\ \\\\\\  rret\\    \\\\ \\\\\\\\";
NSLog(@"%@", [_string stringByReplacingOccurrencesOfString:@"\\" withString:@""]);

---

result is:

 dfsdg  trt tww t     rret     

Answer 5

If its URL Encoded, you are probably looking for:

stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding

Answer 6

Hope this helps:

-(NSString *)unescape:(NSString *)string 
{
    if ([string rangeOfString:@"\\"].location != NSNotFound)
    {
        [string stringByReplacingCharactersInRange:@"\\" withString:@"\\"];
    }
    else if ([string rangeOfString:@"\\\\"].location != NSNotFound)
    {
        [string stringByReplacingCharactersInRange:@"\\\\" withString:@"\\"];
    }
    else if ([string rangeOfString:@"\\\\"].location != NSNotFound)
    {
        [string stringByReplacingCharactersInRange:@"\\\\" withString:@"\\"];
    }
}