Move item inside list?

Question

In Python, how to move an element to a specific index in a list?

Answer 1

Use the insert method for the list:

 l = list(...) l.insert(index, item) 

Alternatively, you can use fragment notation:

 l[index:index] = [item] 

If you want to move an element that is already in the list to the specified position, you will need to delete it and insert it into a new position:

 l.insert(newindex, l.pop(oldindex)) 

Answer 2

A slightly shorter solution that only moves the element to the end, not anywhere else:

 l += [l.pop(0)] 

For example:

 >>> l = [1,2,3,4,5] >>> l += [l.pop(0)] >>> l [2, 3, 4, 5, 1] 

Answer 3

If you do not know the position of the element, you may need to find the index first:

 old_index = list1.index(item) 

then move it:

 list1.insert(new_index, list1.pop(old_index)) 

or IMHO a cleaner way:

 try: list1.remove(item) list1.insert(new_index, item) except ValueError: pass 

Answer 4

The solution is very simple, but you need to know the index of the starting position and the index of the new position:

 list1[index1],list1[index2]=list1[index2],list1[index1]