[FIXED] Why does using this user defined function within print output none?

Issue

def rev_sort(thelist):
    '''
    Reverses and then sorts the list entered
    '''
    thelist.sort()
    thelist.reverse()

def main():
    thelist = ["fun", "is", "programming"]
    # rev_sort(thelist)
    print(rev_sort(thelist))
    
main()

Calling main here outputs None, however, if I instead first use the function rev_sort and print the resulting list I get the decided output. However, I would expect it to be fine to do it like this, what's going on?

Solution

def rev_sort(thelist):
    '''
    Reverses and then sorts the list entered
    '''
    thelist.sort()  # sort function return None
    thelist.reverse()  # reverse function returns None.
    return thelist  # you need to return the list back to main. 

def main():
    thelist = ["fun", "is", "programming"]
    print(rev_sort(thelist))
    
main()

Answered By - Nesi

Answer Checked By - Candace Johnson (PHPFixing Volunteer)