Python Program to Left Rotate a List by n

Write a Python program to left rotate a list by n times or positions. In this example, we sliced the list using the position and combined it using arithmetic +.

ltList = [5, 10, 15, 20, 25, 30, 35, 40, 45, 50]

ltRotate = int(input("Enter Position to Left Rotate List Items = "))

print('Original List Items Before Left Rotating')
print(ltList)

list2 = ltList[ltRotate:] + ltList[:ltRotate]

print('\nFinal List Items After Left Rotating')
print(list2)

This Python program uses the for loop to left rotate the list elements by the user given position.

ltList = [11, 22, 33, 44, 55, 66, 77, 88]

ltRotate = int(input("Enter Position to Left Rotate List Items = "))

print('Original List Items Before Left Rotating')
print(ltList)

for i in range(ltRotate):
    firstValue = ltList[0]
    for j in range(len(ltList) - 1):
        ltList[j] = ltList[j + 1]
    ltList[len(ltList) - 1] = firstValue

print('Final List Items After Left Rotating')
print(ltList)

Enter Position to Left Rotate List Items = 6
Original List Items Before Left Rotating
[11, 22, 33, 44, 55, 66, 77, 88]
Final List Items After Left Rotating
[77, 88, 11, 22, 33, 44, 55, 66]

This example allows the user to enter the list size, items, and rotation number, and left rotate the list items by a given number.

def printListItems(ltList):
    for i in range(len(ltList)):
        print(ltList[i], end = '   ')

ltList = []
ltListTot = int(input("Total Number of Left Rotate List Items = "))

for i in range(1, ltListTot + 1):
    ltListvalue = int(input("Please enter the %d List Item = "  %i))
    ltList.append(ltListvalue)

ltRotate = int(input("Enter Position to Left Rotate List Items = "))

print('\nOriginal List Items Before Left Rotating')
printListItems(ltList)

for i in range(ltRotate):
    firstValue = ltList[0]
    for j in range(len(ltList) - 1):
        ltList[j] = ltList[j + 1]
    ltList[len(ltList) - 1] = firstValue
    
print('\nFinal List Items After Left Rotating')
printListItems(ltList)

Total Number of Left Rotate List Items = 7
Please enter the 1 List Item = 30
Please enter the 2 List Item = 40
Please enter the 3 List Item = 50
Please enter the 4 List Item = 70
Please enter the 5 List Item = 90
Please enter the 6 List Item = 120
Please enter the 7 List Item = 180
Enter Position to Left Rotate List Items = 2

Original List Items Before Left Rotating
30   40   50   70   90   120   180   
Final List Items After Left Rotating
50   70   90   120   180   30   40   

This Python program will help to left rotate a list by n using a while loop.

def printListItems(ltList):
    i = 0
    while i < len(ltList):
        print(ltList[i], end = '   ')
        i = i + 1

ltList = []
ltListTot = int(input("Total Number of Left Rotate List Items = "))
i = 1
while i <= ltListTot:
    ltListvalue = int(input("Please enter the %d List Item = "  %i))
    ltList.append(ltListvalue)
    i = i + 1

ltRotate = int(input("Enter Position to Left Rotate List Items = "))

print('\nOriginal List Items Before Left Rotating')
printListItems(ltList)

i = 0
while i < ltRotate:
    firstValue = ltList[0]
    j = 0
    while j < len(ltList) - 1:
        ltList[j] = ltList[j + 1]
        j = j + 1
    i = i + 1
    ltList[len(ltList) - 1] = firstValue 

   
print('\nFinal List Items After Left Rotating')
printListItems(ltList)

Total Number of Left Rotate List Items = 8
Please enter the 1 List Item = 23
Please enter the 2 List Item = 45
Please enter the 3 List Item = 67
Please enter the 4 List Item = 98
Please enter the 5 List Item = 89
Please enter the 6 List Item = 11
Please enter the 7 List Item = 16
Please enter the 8 List Item = 87
Enter Position to Left Rotate List Items = 3

Original List Items Before Left Rotating
23   45   67   98   89   11   16   87   
Final List Items After Left Rotating
98   89   11   16   87   23   45   67