Question

I want to replace multiple elements in my string in Objective-C.

In PHP you can do this:

str_replace(array("itemtoreplace", "anotheritemtoreplace", "yetanotheritemtoreplace"), "replacedValue", $string);

However in objective-c the only method I know is NSString replaceOccurancesOfString. Is there any efficient way to replace multiple strings?

This is my current solution (very inefficient and.. well… long)

NSString *newTitle = [[[itemTitleField.text stringByReplacingOccurrencesOfString:@"'" withString:@""] stringByReplacingOccurrencesOfString:@" " withString:@"'"] stringByReplacingOccurrencesOfString:@"^" withString:@""];

See what I mean?

Thanks,
Christian Stewart

Answer 1

If this is something you’re regularly going to do in this program or another program, maybe make a method or conditional loop to pass the original string, and multi-dimensional array to hold the strings to find / replace. Probably not the most efficient, but something like this:

// Original String
NSString *originalString = @"My^ mother^ told me not to go' outside' to' play today. Why did I not listen to her?";

// Method Start
// MutableArray of String-pairs Arrays
NSMutableArray *arrayOfStringsToReplace = [NSMutableArray arrayWithObjects:
                                           [NSArray arrayWithObjects:@"'",@"",nil], 
                                           [NSArray arrayWithObjects:@" ",@"'",nil], 
                                           [NSArray arrayWithObjects:@"^",@"",nil], 
                                           nil];

// For or while loop to Find and Replace strings
while ([arrayOfStringsToReplace count] >= 1) {
    originalString = [originalString stringByReplacingOccurrencesOfString:[[arrayOfStringsToReplace objectAtIndex:0] objectAtIndex:0]
                                              withString:[[arrayOfStringsToReplace objectAtIndex:0] objectAtIndex:1]];
    [arrayOfStringsToReplace removeObjectAtIndex:0];
}

// Method End

Output:

2010-08-29 19:03:15.127 StackOverflow[1214:a0f] My'mother'told'me'not'to'go'outside'to'play'today.'Why'did'I'not'listen'to'her?