Reversing a dict?

[krumblebunk@gmail.com]

Hi - further to my earlier query regarding partial matches (which with
all your replies enabled me to advance my understanding, thanks), I
now need to reverse a dict.

I know how to reverse a list (with the reverse method - very handy),
but it doesn't seem possible to reverse a dict.

I suspect what I need to do is somehow go from:

thelist=list(th edict)
thelist.reverse ()
thedict=dict(th elist)

Does anyone know how to convert / or reverse a dict?

thanks

kb.

[cokofreedom@gmail.com]

Re: Reversing a dict?

On May 6, 5:20 pm, krumbleb...@gma il.com wrote:

Hi - further to my earlier query regarding partial matches (which with
all your replies enabled me to advance my understanding, thanks), I
now need to reverse a dict.
>
I know how to reverse a list (with the reverse method - very handy),
but it doesn't seem possible to reverse a dict.
>
I suspect what I need to do is somehow go from:
>
thelist=list(th edict)
thelist.reverse ()
thedict=dict(th elist)
>
Does anyone know how to convert / or reverse a dict?
>
thanks
>
kb.

Issue 1: A dictionary is not ordered so cannot be reversed, as is.

Saw something like this though:

info = {"PHP":"17th May",
"Perl":"15t h June",
"Java":"7th June",
"Python":"2 6th May",
"Tcl":"12th July",
"MySQL":"24 th May"}

topics = info.keys()
topics.sort()
topics.reverse( )

for topic in topics:
print "Next",topic,"c ourse starts",info[topic]

[krumblebunk@gmail.com]

Re: Reversing a dict?

Thanks all!!

kb.

[Paul Hankin]

Re: Reversing a dict?

On May 6, 4:24 pm, cokofree...@gma il.com wrote:

On May 6, 5:20 pm, krumbleb...@gma il.com wrote:
>
>
>

Hi - further to my earlier query regarding partial matches (which with
all your replies enabled me to advance my understanding, thanks), I
now need to reverse a dict.

>

I know how to reverse a list (with the reverse method - very handy),
but it doesn't seem possible to reverse a dict.

>

I suspect what I need to do is somehow go from:

>

thelist=list(th edict)
thelist.reverse ()
thedict=dict(th elist)

>

Does anyone know how to convert / or reverse a dict?

>

thanks

>

kb.

>
Issue 1: A dictionary is not ordered so cannot be reversed, as is.
>
Saw something like this though:
>
info = {"PHP":"17th May",
       "Perl":"15t h June",
       "Java":"7th June",
       "Python":"2 6th May",
       "Tcl":"12th July",
       "MySQL":"24 th May"}
>
topics = info.keys()
topics.sort()
topics.reverse( )
>
for topic in topics:
   print "Next",topic,"c ourse starts",info[topic]

Better:

for topic, when in sorted(topics.i teritems(), reverse=True):
print 'Next %s course starts %s' % (topic, when)

--
Paul Hankin