What does this syntax mean in a for loop? : return [-x for x in lst]

Question

I encountered a problem online where I had to write a function that takes a list of numbers and I have to return its additive inverse. This was one of the answers but I don't understand how does that exactly work?:

def invert(lst):
    return [-x for x in lst]

That's a *list comprehension* - look it up, it's a very useful Python technique. — jasonharper, Jul 30 '23 at 20:27
Make this a running example that prints the return value. Is it clear? — tdelaney, Jul 30 '23 at 20:27
[What does "list comprehension" and similar mean? How does it work and how can I use it?](https://stackoverflow.com/q/34835951/11082165) — Brian61354270, Jul 30 '23 at 20:28

score -1 · Answer 1 · answered Jul 30 '23 at 20:31

-1

def invert(lst):
    return [-x for x in lst]

=

def invert(lst):
   return_list = []
   for x in lst:
      return_list.append(-x)
   return return_list

answered Jul 30 '23 at 20:31

Tobias

1

1

There is 0 need to answer questions like this - perfect duplicates exist. – luk2302 Jul 30 '23 at 20:40
Answer needs supporting information Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](https://stackoverflow.com/help/how-to-answer). – moken Aug 01 '23 at 11:54
@luk2302 but sometimes people like me really want to help people(yes nice people on stackoverflow they are here) – Tobias Aug 02 '23 at 12:28
If you don't have time to enter this,just do comment – Tobias Aug 02 '23 at 12:28

What does this syntax mean in a for loop? : return [-x for x in lst]

1 Answers1