 # Python Program to left shift elements in an array

In this simple python program, we need to left shift elements in an array. It's an intermediate-level python program.

To understand this example, you should have knowledge of the following Python programming topics:

## What is the left shift or left rotate array?

In this simple python program, we need left rotate the elements of the array n times. An array in python is a set of elements of the same type indexed by a common variable. Array elements are stored in the sequential list as array= the first element, array = second, like that.

For example, consider an array A contains elements 1,2,3,4,5 Array A = [ 1, 2, 3, 4, 5 ] So we assume we want to rotate the elements by two times left.

• In the first rotation, the array will be like this A = [2, 3, 4, 5, 1]
• after the second rotation, the array will be changed to A =[3, 4, 5, 1, 2]

like this, we can rotate any number of times.

## How to left shift an array in python?

Let us take the basic python program logic, we open a `for loop`, then save the array's first element into a variable. Open inner for loop to left-shift the elements by one and append the last element from the saved variable. The outer for loop in python will continue until the number of times we need to left rotate the elements.

### ALGORITHM

STEP 1: Initialize an array using some elements. And assign a value to n as the number of times we want to left rotate the array in python language.

STEP 2: Now we display the original array using a `for loop` from zero to the length of an array using the `len()` method and `range()` method in python programming.

STEP 3: Open the outer for loop till the number n from zero using the range method.

STEP 4: Store the first element arr[i] to a variable.

STEP 5: Open the inner loop to traverse from the first element of the array to the length of the array minus one. We have to use less than one to append the last element from the variable.

STEP 6: Apply the left shift by using the method arr[j] = arr[j+1] and it will change the first element as the second element.

STEP 7: Append the last element of the array from the variable we stored the original array's first element.

STEP 8: Use a `for loop` and `print` statement print the resultant array.

## Python Source Code

```                                          ```arr = [1, 2, 3, 4, 5];

n = 1;    # how many times array should be shifted

print("Original array: ");
for i in range(0, len(arr)):    # displaying the first or real array
print(arr[i]),

for i in range(0, n):    # rotate the element of array using for loop

first = arr;    # saving the first element to a variable

for j in range(0, len(arr)-1):

arr[j] = arr[j+1];    #shifting to left by one

arr[len(arr)-1] = first;    # adding the first element to array from the variable

print();

print("Array after left rotation: ");
for i in range(0, len(arr)):
print(arr[i]),    ```
```

## OUTPUT

```Original array:
1
2
3
4
5

Array after left rotation:
2
3
4
5
1```
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