Oct 15, 2010 · I find (contrary to some other suggestions) that l.reverse() is by far the fastest way to reverse a long list in Python 3 and 2. I'd be interested to know if others can replicate these timings. l[::-1] is probably slower because it copies the list prior to reversing it. Adding the list() call around the iterator made by reversed(l) must add ...

Jan 10, 2011 · Nit: "Slicing Python lists always creates copies"—except when they are assigned to, as in a[2:4] = reversed(a[2:4]) in the OP's example. People may be led to think that x = reversed(x) and x.reverse() both modify x , but they are fundamentally different operations in Python, and their results differ when x is not a variable, as shown here.

In Python, what is the best way to create a new list whose items are the same as those of some other list, but in reverse order? (I don't want to modify the existing list in place.) Here is one solution that has occurred to me:

Feb 10, 2009 · How this answer works: it creates a sliced copy of the list with the parameters: start point: unspecified (becomes length of list so starts at end), end point: unspecified (becomes some magic number other than 0, probably -1, so ends at start) and step: -1 (iterates backwards through list, 1 item at a time).

Oct 19, 2008 · Step 1: Figure out the base case. What’s the simplest list you could get? If you get an list with 0 or 1 element, that’s pretty easy to sum up. if len(l) == 0: #base case return [] Step 2: You need to move closer to an empty list with every …

def reverse_list(self,node): if node is None: return //list is empty elif node.next is None: self.head = node // changing the head to last node after reversal return else: reverse_list(node.next) //call the function recursively until the end of the list node.next.next = node //reverse the link node.next = …

For the Python list slicing syntax, list[start:end:step] will get a sliced list with items starting with list[start], but list[end] is excluded. As a result, in your case, L[10:0:-1] will exclude L[0], i.e., 0, and L[10::-1] will work as you expect. When the start or end is a negative number, it means it counts from the end of the list.

def reverse_list(head): new_head = None # this is where we build the reversed list (reusing the existing nodes) while head: temp = head # temp is a reference to a node we're moving from one list to the other head = temp.next # the first two assignments pop the node off the front of the list temp.next = new_head # the next two make it the new ...

Sep 20, 2016 · Reversing a list in Python. 2. Alternate Python List Reverse Solution Needed. 1. Reverse Part of a List. 0 ...

Sep 2, 2011 · The requirement in this question calls for a list of integers of size 10 in descending order. So, let's produce a list in python. # This meets the requirement. # But it is a bit harder to wrap one's head around this. right? >>> range(10-1, -1, -1) [9, 8, 7, 6, 5, 4, 3, 2, 1, 0] # let's find something that is a bit more self-explanatory. Sounds ...