Removing objects from NSMutableArray that are also contained in another NSMutableArray - ios

Question

I have two array, called array1 and array2. I would like to remove every object from array1 that's value of the "nameId" key can be find in both array. Actually I'm trying it in a for loop, but it doesn't make sense. It doesn not crash, it just simply calls the log in the else statement, that I don't understand why happens. Maybe somebody could show me the right solution.
NSMutableArray *newArray = [self.array1 mutableCopy];
for (PFObject * object in newArray) {
PFObject *placeholderObject = object;
for (PFObject *object2 in self.array2) {
if ([placeholderObject[#"nameId"] isEqualToString:object2[#"nameId"]]) {
[self.array1 removeObject:object];
NSLog (#"EXISTING OBJECT FOUND %#", object);
} else {
NSLog(#"UNIQUE OBJECT FOUND %#", idO[#"hirCime"]);
}
}
}

Answer 1

When creating a mutableCopy of an array you create a new array with a copy of every object in it but they aren't the same ones, so object is a member of newArray but is not a member of self.array1 so you can't remove it from that array.
This should work:
// Creates a new empty mutable array
NSMutableArray *newArray = [#[] mutableCopy];
for (PFObject *object in self.array) {
BOOL found = NO;
for (PFObject *object2 in self.array2) {
if ([object[#"nameId"] isEqualToString:object2[#"nameId"]]) {
found = YES;
NSLog (#"EXISTING OBJECT FOUND %#", object);
break;
} else {
NSLog(#"UNIQUE OBJECT FOUND %#", idO[#"hirCime"]);
}
}
if (!found) {
[newArray addObject:[object copy]];
}
}
// And maybe you want this
self.array = newArray;