Sort a sublist of elements in a list leaving the rest in place

Question

Say I have a sorted list of strings as in:

[\'A\', \'B\' , \'B1\', \'B11\', \'B2\', \'B21\', \'B22\', \'C\', \'C1\', \'C11\', \'C2\']

Now I wan

Answer 1

def compound_sort(input_list, natural_sort_prefixes=()):
    padding = '{:0>%s}' % len(max(input_list, key=len))
    return sorted(
        input_list, 
        key = lambda li: \
            ''.join(
                [li for c in '_' if not li.startswith(natural_sort_prefixes)] or 
                [c for c in li if not c.isdigit()] + \
                [c for c in padding.format(li) if c.isdigit()]
            )
        )

This sort method receives:

• input_list: The list to be sorted,
• natural_sort_prefixes: A string or a tuple of strings.

List items targeted by the natural_sort_prefixes will be sorted naturally. Items not matching those prefixes will be sorted lexicographically.

This method assumes that the list items are structured as one or more non-numerical characters followed by one or more digits.

It should be more performant than solutions using regex, and doesn't depend on external libraries.

You can use it like:

print compound_sort(['A', 'B' , 'B11', 'B1', 'B2', 'C11', 'C2'], natural_sort_prefixes=("A","B"))

# ['A', 'B', 'B1', 'B2', 'B11', 'C11', 'C2']