compare dictionary values

[Marc 'BlackJack' Rintsch]

In <dp4124$pki$1 at solaris.cc.vt.edu>, rbt wrote:

> What's a good way to compare values in dictionaries?

Look them up and then compare!?  ;-)

> I want to find 
> values that have changed. I look for new keys by doing this:
> 
> new = [k for k in file_info_cur.iterkeys() if k not in 
> file_info_old.iterkeys()]
>          if new == []:
>              print new, "No new files."
>          else:
>              print new, "New file(s)!!!"
> 
> My key-values pairs are filepaths and their modify times. I want to 
> identify files that have been updated or added since the script last ran.

This looks up each `key` from the `new` dictionary and compares the value
with the `old` one.  If it's not equal or the key is not present in `old`
the key is appended to the `result`::

 def new_and_changed_keys(old, new):
     result = list()
     for (key, value) in new:
         try:
             if old[key] != value:
                 result.append(key)
         except KeyError:
             result.append(key)
     return result

Ciao,
	Marc 'BlackJack' Rintsch