Sort a list in Python, ignore blanks and case

Question

I have a list (of dictionary keys), which I need to sort. This is my list:

listToBeSorted = ["Right  Coronary Artery 2", "Right Coronary Artery 1", "RIght Coronary Artery 3"]

Obviously, the order in which I'd like to have these items sorted would be:

["Right Coronary Artery 1", "Right  Coronary Artery 2", "RIght Coronary Artery 3"]

So I need to find a way to sort, ignoring the double blanks in the first item, and the uppercase "I" in the last item.

I tried the following sorting mechanisms:

1. Plain sorting

   sortedList = sorted(listToBeSorted)
   

   will produce:

   ['RIght Coronary Artery 3',
    'Right  Coronary Artery 2',
    'Right Coronary Artery 1']
   

2. Sorting, ignoring case:

   sortedList = sorted(listToBeSorted, key=str.casefold)
   

   will produce:

   ['Right  Coronary Artery 2',
    'Right Coronary Artery 1',
    'RIght Coronary Artery 3']
   

3. Sorting, eliminating all blanks

   sortedList = sorted(listToBeSorted, key=lambda x: ''.join(x.split()))
   

   will produce:

   ['RIght Coronary Artery 3',
    'Right Coronary Artery 1',
    'Right  Coronary Artery 2']
   

I cannot change the entries themselves, as I need them to access the items in a dictionary later.

I eventually converted the list entries into a tuple, added an uppercase version without blanks, and sorted the list by the 2nd element of the tuple:

sortedListWithTwin = []
    
# Add an uppercase "twin" without whitespaces
for item in listToBeSorted:
  sortString = (item.upper()).replace(" ","")
  sortedListWithTwin.append((item, sortString))
       
# Sort list by the new "twin"
sortedListWithTwin.sort(key = lambda x: x[1])
    
# Remove the twin
sortedList = []
for item in sortedListWithTwin:
  sortedList.append(item[0])

This will produce the desired order:

['Right Coronary Artery 1',
 'Right  Coronary Artery 2',
 'RIght Coronary Artery 3']

However, this solution seems very cumbersome and inefficient. What would be a better way to solve this?

Answer 1

sort using lambda

sortedList = sorted(listToBeSorted, key=lambda x: x.casefold().replace(" ", ""))
print(sortedList)

If you don't want to use replace for some reason. You could even use regex.
re.sub() function will replace all the whitespaces characters with an empty string. \s+ matches one or more consecutive whitespaces. Maintaining casefold() function to ignore case.

import re

sortedList = sorted(listToBeSorted, key=lambda x: re.sub(r"\s+", "", x.casefold()))
print(sortedList)

Output:

['Right Coronary Artery 1', 
'Right Coronary Artery 2', 
'RIght Coronary Artery 3']