Python dictionary search values for keys using regular expression

Question

I am trying to implement to search for a value in Python dictionary for specific key values (using regular expression as a key).

Example:

I have a Python dictionary which has values like:

{'account_0':123445,'seller_account':454545,'seller_account_0':454676, 'seller_account_number':3433343} 

I need to search for values whose key has 'seller_account'? I wrote a sample program but would like to know if something can be done better. Main reason is I am not sure of regular expression and miss out something (like how do I set re for key starting with 'seller_account'):

#!usr/bin/python import re my_dict={'account_0':123445,'seller_account':454545,'seller_account_0':454676, 'seller_account_number':3433343}  reObj = re.compile('seller_account')  for key in my_dict.keys():         if(reObj.match(key)):                 print key, my_dict[key]  ~ home> python regular.py  seller_account_number 3433343 seller_account_0 454676 seller_account 454545 

Answer 1

If you only need to check keys that are starting with "seller_account", you don't need regex, just use startswith()

my_dict={'account_0':123445,'seller_account':454545,'seller_account_0':454676, 'seller_account_number':3433343}  for key, value in my_dict.iteritems():   # iter on both keys and values         if key.startswith('seller_account'):                 print key, value 

or in a one_liner way :

result = [(key, value) for key, value in my_dict.iteritems() if key.startswith("seller_account")] 

NB: for a python 3.X use, replace iteritems() by items() and don't forget to add () for print.

Answer 2

You can solve this with dpath.

http://github.com/akesterson/dpath-python

dpath lets you search dictionaries with a glob syntax on the keys, and to filter the values. What you want is trivial:

$ easy_install dpath >>> dpath.util.search(MY_DICT, 'seller_account*') 

... That will return you a big merged dictionary of all the keys matching that glob. If you just want the paths and values:

$ easy_install dpath >>> for (path, value) in dpath.util.search(MY_DICT, 'seller_account*', yielded=True): >>> ... # do something with the path and value