Python: Moves the specified amount of elements to the start of the list

Last update on April 19 2025 13:00:50 (UTC/GMT +8 hours)

Move Elements to Start

Write a Python program to move the specified number of elements to the start of the given list.

Use slice notation to get the two slices of the list and combine them before returning.

Sample Solution:

Python Code:

# Define a function named 'move_start' that moves elements of a list by a given 'offset.'
def move_start(nums, offset):
    return nums[-offset:] + nums[:-offset]
    # Slices the list from the negative 'offset' position to the end (equivalent to moving elements from the end to the start) and concatenates it with the portion from the start to the negative 'offset' position.

# Test the 'move_start' function with different lists and offsets.
print(move_start([1, 2, 3, 4, 5, 6, 7, 8], 3))
# Move the elements three positions to the start. (Expected output: [6, 7, 8, 1, 2, 3, 4, 5])

print(move_start([1, 2, 3, 4, 5, 6, 7, 8], -3))
# Move the elements three positions to the end. (Expected output: [4, 5, 6, 7, 8, 1, 2, 3])

print(move_start([1, 2, 3, 4, 5, 6, 7, 8], 8))
# The 'offset' equals the length of the list, resulting in the same list.

print(move_start([1, 2, 3, 4, 5, 6, 7, 8], -8))
# The negative 'offset' equals the negative length of the list, resulting in the same list.

print(move_start([1, 2, 3, 4, 5, 6, 7, 8], 7))
# Move the elements seven positions to the start. (Expected output: [2, 3, 4, 5, 6, 7, 8, 1])

print(move_start([1, 2, 3, 4, 5, 6, 7, 8], -7))
# Move the elements seven positions to the end. (Expected output: [8, 1, 2, 3, 4, 5, 6, 7])

Sample Output:

[6, 7, 8, 1, 2, 3, 4, 5]
[4, 5, 6, 7, 8, 1, 2, 3]
[1, 2, 3, 4, 5, 6, 7, 8]
[1, 2, 3, 4, 5, 6, 7, 8]
[2, 3, 4, 5, 6, 7, 8, 1]
[8, 1, 2, 3, 4, 5, 6, 7]

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to move all odd numbers in a list to the beginning while keeping their order.
Write a Python program to move the last n elements of a list to the start.
Write a Python program to relocate all prime numbers in a list to the beginning, preserving their original order.
Write a Python program to cyclically rotate a list so that a specified sublist from the end is moved to the start.

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