reverse.py

# Function to reverse arr[] from index start to end 
def rverseArray(arr, start, end): 
    while (start < end): 
        temp = arr[start] 
        arr[start] = arr[end] 
        arr[end] = temp 
        start += 1
        end = end-1
  
# Function to left rotate arr[] of size n by d 
def leftRotate(arr, d): 
    n = len(arr) 
    rverseArray(arr, 0, d-1) 
    rverseArray(arr, d, n-1) 
    rverseArray(arr, 0, n-1) 
  
# Function to print an array 
def printArray(arr): 
    for i in range(0, len(arr)): 
        print (arr[i]) 
  
# Driver function to test above functions 
arr = [1, 2, 3, 4, 5, 6, 7] 
leftRotate(arr, 2) # Rotate array by 2 
printArray(arr)