in conclusion
- (void)viewDidLoad { [super viewDidLoad]; self.testArray = [NSMutableArray arrayWithObjects:@"cat",@"dog",@"man",@"dog",@"dog", nil]; } - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{ // [self removeObjectWithInset]; // [self removeObjWithIndex]; // [self removeObjWithObj]; // [self removeObj]; // [self removeTheObjWithInset]; NSLog(@"%@",self.testArray); } /** delete by index */ - (void)removeObjWithIndex{ for (int i = 0; i< self.testArray.count; i++) { NSString *var = self.testArray[i]; if ([var isEqualToString:@"dog"]) { [self.testArray removeObjectAtIndex:i]; // If you delete all isEqual obj, do not add Break // If you delete the first one, add break break ; } } } /** Not adding break will cause crash Even adding break will delete all dogs */ - (void)removeObjWithObj{ for (NSString *str in self.testArray) { if ([str isEqualToString:@"dog"]) { [self.testArray removeObject:str]; break; } } } /** It is also possible to delete it directly */ - (void)removeObj{ [self.testArray removeObject:@"dog"]; } /** Remove via NSInset */ - (void)removeObjectWithInset{ NSIndexSet *indexSet = [self.testArray indexesOfObjectsPassingTest:^BOOL(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) { return [obj isEqualToString:@"dog"]; }]; [self.testArray removeObjectsAtIndexes:indexSet]; } /** delete the second dog */ - (void)removeTheObjWithInset{ NSMutableArray *idxArray = [NSMutableArray array]; for (int i = 0; i< self.testArray.count; i++) { NSString *str = self.testArray[i]; if ([str isEqualToString:@"dog"]) { [idxArray addObject: [NSString stringWithFormat:@"%d",i]]; } } NSInteger getIndex; getIndex = [idxArray[1] integerValue]; [self.testArray removeObjectAtIndex:getIndex]; }