Python – Nearest K Sort

Given a List of elements, perform sort on basis of its distance from K.

Input : test_list = [6, 7, 4, 11, 17, 8, 3], K = 10 
Output : [11, 8, 7, 6, 4, 17, 3] 
Explanation : 11-10 = 1; < 10 – 8 = 2 .. Ordered by increasing difference.

Input : test_list = [6, 7, 4, 11], K = 10 
Output : [11, 7, 6, 4] 
Explanation : 11-10 = 1; < 10 – 7 = 3 .. Ordered by increasing difference. 

Method #1 : Using sort() + abs()

In this, we perform sorting using sort() and abs() is used to get the difference, used for logic formation to perform sort operation upon.

Python3

# Python3 code to demonstrate working of
# Nearest K Sort
# Using sort() + abs()

# getting absolute difference
def get_diff(ele):

    # returning absolute difference
    return abs(ele - K)


# initializing list
test_list = [6, 7, 4, 11, 17, 8, 3]

# printing original list
print("The original list is : " + str(test_list))

# initializing K
K = 10

# performing inplace sort using sort()
test_list.sort(key=get_diff)

# printing result
print("Sorted List : " + str(test_list))

Output

The original list is : [6, 7, 4, 11, 17, 8, 3]
Sorted List : [11, 8, 7, 6, 4, 17, 3]

Method #2 : Using sorted() + lambda + abs()

Similar to above method, here, sorted() is used to perform sort operation and rather than calling external function, lambda is used to provide sorting logic.

Python3

# Python3 code to demonstrate working of
# Nearest K Sort
# Using sorted() + abs() + lambda

# initializing list
test_list = [6, 7, 4, 11, 17, 8, 3]

# printing original list
print("The original list is : " + str(test_list))

# initializing K
K = 10

# sorted() used to perform sorting, lambda function to get logic
res = sorted(test_list, key=lambda ele: abs(ele - K))

# printing result
print("Sorted List : " + str(res))

Output

The original list is : [6, 7, 4, 11, 17, 8, 3]
Sorted List : [11, 8, 7, 6, 4, 17, 3]