greetings, fellow ventriloquists;
the exchanges on this list are great tutorials; sometimes i don't quite
get the finer points; like here:
On Mon, Jun 16, 2008 at 10:41 AM, GTXY20 <[EMAIL PROTECTED]> wrote:
> Let's say I have a list like the following:
>
> a = ['a1','a2','a3','a4','a5','a6']
>
> and then I have dictionary like the following:
>
> b = {'a1,a2,a3':'super'}
>
> I need some direction and thoughts on how I might seach the list for the
> string (the key in dict b) sequence in list a and replace the occurance with
> the value from dict b. At the end I would like to have list a represented
> as:
>
> a = ['super', 'a4', 'a5', 'a6']
the solution:
From: Tiago Saboga <[EMAIL PROTECTED]>
The following works for your example. I assume the values in the a
list are unique.
for key in b:
keylist = key.split(',')
if keylist < a:
i = a.index(keylist[0])
print a[:i] + [b[key]] + a[i+len(keylist):]
---------------------
but this works, too;
>>> a = ['a1','a2','a3','a4','a5','a6']
>>> b = {'a1,a2,a3':'super'}
>>> for key in b:
... keylist = key.split(',')
... i = a.index(keylist[0])
... print [b[key]] + a[i+len(keylist):]
...
['super', 'a4', 'a5', 'a6']
-----------------------
now, i get it, mostly; but keylist being shorter than the list "a"
>>> keylist < a
True
doesn't seem relevant, unless the 'for' statement were to go on and on;
and if a[:i] = zilch:
>>> for key in b:
... keylist = key.split(',')
... if keylist < a: # DOES THIS MEAN LENGTH?
... i = a.index(keylist[0]) # a[index of first item in the key == 0];
... print a[:i] # a[:0] == pre-first item == None;
...
[]
then why bother with that part?
---------------------------------
finally, how might the code handle a dictionary with more than one item?
since i figured the line
if keylist < a:
might be part of some kind of iteration, say, until all of the items in
"a" had been replaced by dictionary values,
this is as far as i got:
>>> a = ['a','b','c','d','e','f']
>>> b = {'a,b':'firstval', 'c,d':'secondval'}
>>> for key in b:
... keylist = key.split(',')
... if keylist < a:
... i = a.index(keylist[0])
... print a[:i] + [b[key]] + a[i+len(keylist):]
...
['firstval', 'c', 'd', 'e', 'f']
but 'secondval' did not replace 'c' and 'd' in "a";
what am i missing? thanks, imputerate
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
