Python | Sort alternate numeric and alphabet list

Sometimes, while performing sorting in list, we have a problem in which we need to perform particular type of sorting in which we need to sort in alternate ways in which we have numerics and alphabets sorted in order. Lets discuss certain ways in which this task can be performed.

Method #1 : Using isalpha() + isnumeric() + zip_longest()
The combination of above methods can be used to perform this task. In this, we separate the numeric and alphabets and then perform a sort on them separately and join using zip_longest().

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 code to demonstrate 
# Sort alternate numeric and alphabet list
# using isalpha() + isnumeric() + zip_longest()
from itertools import zip_longest
  
# Initializing list
test_list = ['3', 'B', '2', 'A', 'C', '1']
  
# printing original list
print("The original list is : " + str(test_list))
  
# Sort alternate numeric and alphabet list
# using isalpha() + isnumeric() + zip_longest()
num_list = sorted(filter(str.isnumeric, test_list), 
                       key = lambda sub: int(sub))
  
chr_list = sorted(filter(str.isalpha, test_list))
res = [ele for sub in zip_longest(num_list, chr_list)
                              for ele in sub if ele]
      
# printing result 
print ("List after performing sorting : " + str(res))

chevron_right


Output :

The original list is : ['3', 'B', '2', 'A', 'C', '1']
List after performing sorting : ['1', 'A', '2', 'B', '3', 'C']

 

Method #2 : Using sorted() + key + lambda + isnumeric()
The combination of above methods can be used to perform this task. In this, we perform the sorting in alternate manner using ord() and lambda function, testing using isnumeric().

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 code to demonstrate 
# Sort alternate numeric and alphabet list
# using sorted() + key + lambda + isnumeric()
from itertools import zip_longest
  
# Initializing list
test_list = ['3', 'B', '2', 'A', 'C', '1']
  
# printing original list
print("The original list is : " + str(test_list))
  
# Sort alternate numeric and alphabet list
# using sorted() + key + lambda + isnumeric()
res = sorted(test_list, key = lambda ele : (int(ele), 0)
      if ele.isnumeric()
      else ((ord(ele) - 64) % 26, 1))
  
# printing result 
print ("List after performing sorting : " + str(res))

chevron_right


Output :

The original list is : ['3', 'B', '2', 'A', 'C', '1']
List after performing sorting : ['1', 'A', '2', 'B', '3', 'C']



My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.