KentThanks again. I have a question (see below).On 26/01/06, Kent Johnson [EMAIL PROTECTED] wrote:
Jon Moore wrote: Hi, I have the following dictionary: pairs = {Jon Moore: [Tony Moore, Stanley Moore],
Simon Nightingale: [John Nightingale, Alan Nightingale],David Willett: [Bernard Willet, Robert Willet],John Jackson: [John Jackson, Peter Jackson],
James Southey: [Richard Southey, Paul Southey],Shaun Forsythe: [William Forsythe, Angus Forsythe],Daniel Geach: [Mike Geach, Andy Geach]}
Where the names represent a son, father and grandfather. I am trying to add a new term and related definitions to the dictionary, but my code does not seem to work: son = raw_input(Please enter the name of the Son: )
if son not in pairs: father = raw_input(Who is the Father?: ) grandfather = raw_input(What is the Grand Father?: ) pairs[son][0] = father
pairs[son][1] = grandfather print \n, son, ,, father, and ,grandfather, have been added. else: print \nThat Son already exists!
The error I get is: pairs[son][0] = father KeyError: 'Steven Bates' Where am I going wrong?The problem is, when you say pairs[son][0] = father
pairs[son] does not yet exist. This is on the left side of anassignment, but it is really an access to pair[son]. It is as if you hadwritten temp = pairs[son] temp[0] = fatherYou get a KeyError accessing pairs[son].
The solution is to create a new list for the (father, grandfather) pair,and assign that to pairs[son]:ancestors = [father, grandfather]pairs[son] = ancestorsYou might want to rethink how you are storing the data. (father,
grandfather) is actually a (son, father) pair so you might want to storethem as another entry in the dictionary. Also two sons could have thesame father and grandfather; with your scheme you will store the
(father, grandfather) pair twice. In general this kind of duplication ofdata is better avoided.Good point, but I have no idea how to do this! Could you show me?
You might also want to Google 'python genealogy'.Kent___Tutor maillist-Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor-- Best RegardsJon Moore
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