Subtracting one arrayList from another arrayList

Question

I have two arrayLists and I am trying to \"subtract\" one arrayList from another. For example, if I have one arrayList [1,2,3] and I am trying to subtract [0, 2, 4] the resu

Answer 1

Try this answer if removeAll() is not what you want. e.g. if you are interested in something like Calculating difference of two lists with duplicates

subtract(a,b)

b.forEach((i)->a.remove(i));

a now contains

[1, 3]

This follows the suggestion of Guava implementors on how to implement subtract

"create an ArrayList containing a and then call remove on it for each element in b."

Which behaves like this implementation used in Apache commons

Difference to removeAll()

[1,2,2,3].removeAll([1,2,3]) //is empty
[1,2,3].forEach((i)->[1,2,2,3].remove(i)); //a is [2]