How to move an element to the first position of a List in groovy

Question

how do I reorder the list say:

['apple', 'banana', 'orange']

if user select banana, the list becomes

['banana', 'apple', 'orange']

Answer 1

Another way to do it:

def list = ['apple', 'banana', 'orange']
// get a reference to the selection (banana)
def pick = list.find { it == 'banana' }
// remove selection from the the list
def newList = list.minus(pick)
// add selection back at the beginning
newList.add(0, pick)

Answer 2

Split into two lists and recombine - easily generalized for non-String lists:

List<String> moveToStart(List<String> original, String input) {
  original.split {it.equals(input)}.flatten()
}

Answer 3

List pickToFirst(List list, int n) {
    return list[n,0..n-1,n+1..list.size()-1]
}

In your case,

    def list = ['apple', 'banana', 'orange']
    def newList = pickToFirst(list, 1)