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Re: Algorithms using Python?

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On Fri, Sep 21, 2012 at 1:45 PM, Dennis Lee Bieber
<wlfraed@ix.netcom.com> wrote:
>         You can probably implement them, but they're not going to be very
> efficient. (And never "remove" an element from the linked-list
> implementation because Python would shift all the other elements, hence
> your "links" become invalid).

I'm not sure what you mean by that last comment.

class Node(object):
    def __init__(self, data, next):
        self.data = data
        self.next = next

class LinkedList(object):
    def __init__(self):
        self._head = None
    def __iter__(self):
        node = self._head
        while node:
            yield node.data
            node = node.next
    def insert_front(self, value):
        self._head = Node(value, self._head)
    def remove(self, value):
        prior, node = None, self._head
        while node:
            if node.data == value:
                if prior:
                    prior.next = node.next
                else:
                    self._head = node.next
                break
            prior, node = node, node.next
        else:
            raise ValueError("value not found")

>>> li = LinkedList()
>>> for char in 'edcba':
...     li.insert_front(char)
...
>>> print ''.join(li)
abcde
>>> li.remove('c')
>>> print ''.join(li)
abde

It seems to work fine to me.

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Thread

Algorithms using Python? Mayuresh Kathe <mayuresh@kathe.in> - 2012-09-21 14:26 +0530
  Re: Algorithms using Python? Joel Goldstick <joel.goldstick@gmail.com> - 2012-09-21 10:41 -0400
  Re: Algorithms using Python? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-09-21 15:45 -0400
  Re: Algorithms using Python? Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-21 14:07 -0600
  Re: Re: Algorithms using Python? Evan Driscoll <driscoll@cs.wisc.edu> - 2012-09-21 15:43 -0500
  Re: Algorithms using Python? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-09-21 17:14 -0400
    Re: Algorithms using Python? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-22 01:28 +0000
      Re: Algorithms using Python? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-09-22 00:29 -0400
  Re: Algorithms using Python? Wayne Werner <wayne@waynewerner.com> - 2012-09-26 10:55 -0500
    Re: Algorithms using Python? 88888 Dihedral <dihedral88888@googlemail.com> - 2012-09-27 04:15 -0700
    Re: Algorithms using Python? 88888 Dihedral <dihedral88888@googlemail.com> - 2012-09-27 04:15 -0700

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