CODEWITHSUNDEEP
pythonpython-3.xlist
ragardner
ragardner

Reputation: 1975

Move single or multiple sequential items in a list to any position

I need to move single or multiple sequential items in a list, by sequential I mean if the items are more than one there are no gaps in their list indexes, here is what I have tried...

def move(x, tomove, idx):
    move_start = tomove[0]
    move_end = tomove[-1] + 1
    if idx == len(x) or idx == len(x) - 1:
        return x[:move_start] + x[move_end:] + x[move_start:move_end]
    elif idx == 0:
        return x[move_start:move_end] + x[:move_start] + x[move_end:]
    else:
        pass

# move to start
print (move([0,1,2,3,4,5,6],
            [2],
            0))
# expected output [2,0,1,3,4,5,6]

# move to end
print (move([0,1,2,3,4,5,6],
            [2],
            6))
# expected output [0,1,3,4,5,6,2]

# move forward single
print (move([0,1,2,3,4,5,6],
            [2],
            3))
# expected output [0,1,3,2,4,5,6]

# move backward single
print (move([0,1,2,3,4,5,6],
            [2],
            1))
# expected output [0,2,1,3,4,5,6]

# move forward multiple
print (move([0,1,2,3,4,5,6],
            [2,3],
            5))
# expected output [0,1,4,5,2,3,6]

# move backward multiple
print (move([0,1,2,3,4,5,6],
            [4,5],
            2))
# expected output [0,1,4,5,2,3,6]

Upvotes: 1

Views: 82

Answers (1)

m0dknight
m0dknight

Reputation: 169

Since you've not mentioned anything about validation like if the given sequence of elements is not present in the original list, the ordering of the main list and given list etc. I've not considered any validations.

Before jumping into code, let's see how to crack the solution. First, you need to identify the existing position of the given list in the main list.

move_list_pos = lis.index(move_list[0])

Now, check whether the given list to be moved forward or backward.

  • If it needs to move backward, then theirs no change in the main list till the new positon, insert the given list, continue the main list except for the given list.
  • If it needs to move forward, then the main list should be there except for the given list in the main list till the new position, add the given list, continue the main list from a new position to end.

Solution code:

def move(lis,move_list,pos):
    move_list_pos = lis.index(move_list[0])
    if pos<move_list_pos:
        return lis[:pos]+move_list+lis[pos:move_list_pos]+lis[move_list_pos+len(move_list):]
    else:
        return lis[:move_list_pos]+lis[move_list_pos+len(move_list):pos+1]+move_list+lis[pos+1:]

Upvotes: 1

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