Removing elements with multiple arguments of an ArrayList

Question

I want to remove an instance of an ArrayList, but with the code I have now it lists the movies removed. I have an ArrayList that takes title, year, genre and balance. The goal is to remove from the list using only title and year.

I have tried a for-each loop, but that leads to ConcurrentModificationException error, and I am not sure how use use Iterators to make it work for this example.

It is supposed to remove the instance specified by title and year so that when it lists the moviesAvailable, the list would be updated. However when listing it shows all movies (probably because it is not actually removing the movie).

If you do not override equals on your Movie class how can anything tell that one instance equals another? — Scary Wombat
– Scary Wombat, Commented May 8, 2019 at 1:53
Possible duplicate of Calling remove in foreach loop in Java — qtopierw
– qtopierw, Commented May 8, 2019 at 1:55
See stackoverflow.com/questions/1196586/…, or use index in for-loop to remove the item. You should not use for-each to remove elements see docs.oracle.com/javase/8/docs/technotes/guides/language/… — qtopierw
– qtopierw, Commented May 8, 2019 at 1:58

Hai Vu · Accepted Answer · 2019-05-08 06:55:44Z

1

One way to remove the targeted movie is via the Collections.removeIf() method:

public void removeMovie() {
    System.out.println("\nRemoving a movie.");
    System.out.print("Enter the title of the movie: ");
    String title = In.nextLine();
    System.out.print("Enter the year: ");
    int year = In.nextInt();
    moviesAvailable.removeIf(movie -> movie.hasType(title, year));
    // other stuff...
}

Note

The removeIf method iterates through your collection and true to its name, removes an element (a movie in this case) which satisfy the condition.
If your entry was not deleted, please check to see if title and year are correct. For example, does title contain a trailing new line?

edited May 8, 2019 at 6:55

answered May 8, 2019 at 2:03

Hai Vu

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3 Comments

T Dizzle Over a year ago

I tried that, but when when it lists the movies whichever one I delete still shows up

Hai Vu Over a year ago

Please check to see if your title and year are correct.

Amal Gupta Over a year ago

I checked this solution. It seems to work. I have used scanner to input movie and year, and the matching happens in a case sensitive manner.

jlco · Accepted Answer · 2019-05-08 02:15:27Z

0

you can do something like

 moviesAvailable.removeIf(m -> m.hasType("s",2));

answered May 8, 2019 at 2:15

jlco

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