I am studying rotating a list, and made a function to rotate the list left and right, but how can I write a code for how many times to rotate? if that makes a sense. I want to pass it as an argument to the functions.
table = [1, 10 ,20, 0, 59, 86, 32, 11, 9, 40]
def rotate_left():
(table.append(table.pop(0)))
return table
print(rotate_left())
def rotate_right():
(table.insert(0,table.pop()))
return table
print(rotate_right())
You can use for loop inside your functions and pass how many times you want to rotate as a argument.
table = [1, 10 ,20, 0, 59, 86, 32, 11, 9, 40]
def rotate_left(rotate_times):
for _ in range(rotate_times):
table.append(table.pop(0))
return table
>>> print(rotate_left(2))
>>> [20, 0, 59, 86, 32, 11, 9, 40, 1, 10]
def rotate_right(rotate_times):
for _ in range(rotate_times):
table.insert(0,table.pop())
return table
>>> print(rotate_right(2))
>>> [1, 10, 20, 0, 59, 86, 32, 11, 9, 40]
NOTE
In above scenario, be aware of the fact that, when you pass a list to a method and modify it inside that method, the changes are made in original list unless you make a deep copy, because list is a mutable type.
So, when you call rotate_left(2), it rotates the original list twice towards left. Then when you call rotate_right(2), it rotates the original list, which is already rotated by rotate_left(2), so we got the list as in initial order.
As, the functions are already modifying the original list, you can remove return table from the function (unless you want a new deep copy of list). And simply print the list after that like:
def rotate_left(rotate_times):
for _ in range(rotate_times):
table.append(table.pop(0))
>>> rotate_left(2)
>>> print(table)
>>> [20, 0, 59, 86, 32, 11, 9, 40, 1, 10]
You can write a 'for loop' and use 'range' to decide how many times you want to rotate. In this example 'rotate_left()' is called three times:
table = [1, 10 ,20, 0, 59, 86, 32, 11, 9, 40]
def rotate_left():
(table.append(table.pop(0)))
return table
def rotate_right():
(table.insert(0,table.pop()))
return table
for i in range(3):
print(rotate_left())
You can write a 'loop' and use 'range' to decide how many times you want to loop. In this example, there is a program that asks the user in which direction and how many times to turn and calculates.
def rotate_left(count,table):
for i in range (count):
(table.append(table.pop(0)))
return table
def rotate_right(count,table):
for i in range (count):
(table.insert(0,table.pop()))
return table
def main():
table = [1, 10 ,20, 0, 59, 86, 32, 11, 9, 40]
isSelect = True
while(isSelect):
rotate = int(input("1- Rotate Left\n2- Rotate Right\n: "))
count = int(input("\nHow many times to rotate ?\n: "))
if((rotate == 1 or rotate == 2) and count > 0):
isSelect = False
if (rotate == 1):
print(rotate_left(count,table))
elif (rotate == 2):
print(rotate_right(count,table))
else:
print("\nInvalid Parameter. Please choose again.\n")
main()
