# Python – Adjacent elements in List

PythonServer Side ProgrammingProgramming

When it is required to display adjacent elements in list, a method is defined that uses enumerate and a simple iteration to determine the result.

## Example

Below is a demonstration of the same −

def find_adjacent_elements(my_list):
my_result = []
for index, ele in enumerate(my_list):
if index == 0:
my_result.append((None, my_list[index + 1]))
elif index == len(my_list) - 1:
my_result.append((my_list[index - 1], None))
else:
my_result.append((my_list[index - 1], my_list[index + 1]))
return my_result

my_list = [13, 37, 58, 12, 41, 25, 48, 19, 23]

print("The list is:")
print(my_list)

print("The result is :")
print(find_adjacent_elements(my_list))

## Output

The list is:
[13, 37, 58, 12, 41, 25, 48, 19, 23]
The result is :
[(None, 37), (13, 58), (37, 12), (58, 41), (12, 25), (41, 48), (25, 19), (48, 23), (19, None)]

## Explanation

• A method named ‘find_adjacent_elements’ is defined that takes a list as a parameter, and does enumerates over the list.

• An empty list is created.

• The elements are iterated over using ‘enumerate’ and depending on the value of the index, the output is determined.

• If index value is 0, the element in first index is appended to the empty list.

• If index is equal to length of list minus 1, the element in previous index is appended to empty list.

• Otherwise, both the previous and next elements are appended to the empty list.

• Outside the method, a list is defined and displayed on the console.

• The method is called by passing the required parameter.

• The output is displayed on the console.

Published on 08-Sep-2021 09:10:04