Sort by multiple keys using different orderings [duplicate]

by

There is no built-in way to handle this. For the general case, you must sort twice: first by the secondary sort, then by the primary sort. As @Mark Ransom mentioned in his comment, in many cases the variables are numeric, and so you can use the negative value to flip the ordering.

If you know the type of the variable you’re trying to sort on and how to work with it, you could also write a key function that returns a decreasing value for increasing keys. See this thread for an example for strings. (Basically, you take the negative of the ASCII numerical value of the characters.)

In Python 2, you could also use a cmp function instead of a key, but this will likely make the sort slower. Whether it will make it too slow depends on how big and unsorted the list is. In Python 3, the cmp argument is gone, but as @Mark Ransom notes you could use cmp_to_key.

More Related Contents:

  1. How to display position of an element in an array? [closed]
  2. How to blit a random image from a list Pygame [duplicate]
  3. How to make Firefox headless programmatically in Selenium with Python?
  4. Calling a python script with input within a python script using subprocess
  5. Lag when win.blit() background pygame
  6. How do I format a string using a dictionary in python-3.x?
  7. How can I use `return` to get back multiple values from a for loop? Can I put them in a list?
  8. certificate verify failed: unable to get local issuer certificate
  9. How do I resolve a TesseractNotFoundError?
  10. Accessing attributes on literals work on all types, but not `int`; why? [duplicate]
  11. Print list of lists in separate lines
  12. OpenCV for Python 3.x under Windows [duplicate]
  13. Python 2 and Python 3 dual development
  14. Why do I get an int when I index bytes?
  15. How does one ignore extra arguments passed to a dataclass?
  16. Unsupported operation :not writeable python
  17. Python 3.3 and Installing PyOpenSSL on a Mac
  18. How to remove punctuation marks from a string in Python 3.x using .translate()?
  19. Sorting by absolute value without changing to absolute value
  20. Why isn’t .ico file defined when setting window’s icon?
  21. How to share numpy random state of a parent process with child processes?
  22. Printing result of the zip() function in Python 3 gives “zip object at ” [duplicate]
  23. FutureWarning: The default value of regex will change from True to False in a future version
  24. Multiple keys per value
  25. Python: can’t assign to literal
  26. How to put comments in Django templates?
  27. ImportError: cannot import name ‘_ColumnEntity’ from ‘sqlalchemy.orm.query’
  28. How to write List of lists in csv file in python [duplicate]
  29. With “args” vs without “args” to pass arguments to a thread in Python
  30. How to make print() output UTF-8 in Python 3.0?

Leave a Comment