On Sat, 2 Apr 2016 07:27 am, Fillmore wrote: > > notorious pass by reference vs pass by value biting me in the backside > here. Proceeding in order.
Python is NEITHER pass by reference nor pass by value. Please read this: http://import-that.dreamwidth.org/1130.html before asking any additional questions. > def bringOrderStringToFront(mylist, key): > > for i in range(len(mylist)): > if(mylist[i].startswith(key)): > mylist = [mylist[i]] + mylist[:i] + mylist[i+1:] [mylist[i]] + mylist[:i] + mylist[i+1:] creates a new list. It doesn't modify the existing list. mylist = ... performs an assignment to the LOCAL VARIABLE mylist, setting it to the new list just created. The original list is unchanged. Trick: you can use slicing to write to the original list: mylist[:] = [mylist[i]] + mylist[:i] + mylist[i+1:] Or you can modify the list directly in place: for i in range(len(mylist)): if mylist[i].startswith(key): x = mylist[i] del mylist[i] mylist.insert(0, x) which is better written as: for i, x in enumerate(mylist): if x.startswith(key): del mylist[i] mylist.insert(0, x) or if you prefer: for i, x in enumerate(mylist): if x.startswith(key): mylist[:] = [x] + mylist[:i] + mylist[i+1:] -- Steven -- https://mail.python.org/mailman/listinfo/python-list
