Compare two strings and remove common elements - iphone

Question

I have two comma seperated NSString's & I want to remove the similar characters from first string only.
ex. str1 = 0,1,2,3
str2 = 1,2.
output -> str1 = 0,3 and str2 = 1,2.
I have one option that, seperate both the string with comma seperated values in a array. But it requires two NSArray's & apply loop and then remove the common elements, but it is very tedious job.
So I want some simple & proper solution which avoid the looping.
kindly help me to sort out this.

Answer 1

Try this one:
No loop is required!!!
You have got all the required APIs.
NSString *str1=#"0,1,2,3";
NSString *str2=#"1,2";
NSMutableArray *arr1=[[NSMutableArray alloc]initWithArray:[str1 componentsSeparatedByString:#","]];
[arr1 removeObjectsInArray:[str2 componentsSeparatedByString:#","]];
NSLog(#"arr1 %#",arr1);
/*
NSMutableString *finalString=[NSMutableString new];
for (NSInteger i=0; i<[arr1 count]; i++) {
NSString *str=[arr1 objectAtIndex:i];
[finalString appendString:str];
if (i!=[arr1 count]-1) {
[finalString appendString:#","];
}
}
*/
NSString *finalString=[arr1 componentsJoinedByString:#","];
NSLog(#"finalString %#",finalString);

Answer 2

Something like that ?
NSString *string = #"0,1,2,3";
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"self like '1' OR self like '2'"];
NSLog(#"%#",[[string componentsSeparatedByString:#","] filteredArrayUsingPredicate:predicate]);

Answer 3

id str1=#"aa,ab,ac,cd,ce,cf";
id str2=#"aa,ac,cd,cf";
//no ab and no ce
id cmps1 = [str1 componentsSeparatedByString:#","];
id cmps2 = [str2 componentsSeparatedByString:#","];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"NOT SELF IN %#", cmps2];
NSArray *final = [cmps1 filteredArrayUsingPredicate:predicate];
id str = [final componentsJoinedByString:#","];
NSLog(#"%#", str);

Answer 4

The only solution that I can think of would be this:
NSMutableArray* arr1 = [str1 componentsSeparatedByString:#","] mutableCopy];
NSArray* arr2 = [str2 componentsSeparatedByString:#","];
for (NSString* str in arr2) {
[arr1 removeObject:str];
}
NSString* newString1 = [arr1 componentsJoinedByString:#","];
Is this what you tried? If "str1" looks something like "1,1,2,2,2", then you might have some more work to do here to get rid of the duplicates. But that's basically it.