On 3/5/2010 3:05 AM, jimgardener wrote:
hi
I have two lists of names.I need to find the difference between these
two lists.I tried to do it using sets.But I am wondering if there is a
better way to do it.Please tell me if there is a more elegant way.
thanks,
jim
my code snippet follows..
oldlst=['jon','arya','ned','bran']
newlst=['jaime','jon','cersei']
newlyadded=set(newlst)-set(oldlst)
removed=set(oldlst)-set(newlst)
unchanged=set(oldlst)& set(newlst)
Except for the duplicate calls to set, this is fine. If order and
duplication are irrelevant (and hashability is guaranteed), use sets to
start with.
print '%d were newly added= %s'%(len(newlyadded),list(newlyadded))
print '%d were removed=%s'%(len(removed),list(removed))
print '%d were unchanged=%s'%(len(unchanged),list(unchanged))
this produces the output
--------------
2 were newly added= ['jaime', 'cersei']
3 were removed=['ned', 'arya', 'bran']
1 were unchanged=['jon']
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