How to update keys in dictionary?

Question

I have a {} with a string -> list relationship, like:

'Something.Default.' : ['a=initiator', 'b=00:00:00']
'Something.Session.' : ['b=acceptor', 'c=7039']

I'd like to change keys to drop the last . 'Something.Default.' should become 'Something.Default'.

This is obviously wrong, but it illustrates what I am looking for

for key in my_dictionary:
    key = key[:-1]

How can I iterate over each key and change it?

Can you not fix the source of the data before you build the dictionary? — OneCricketeer, Aug 11 '16 at 19:27

score 4 · Answer 1 · answered Aug 11 '16 at 19:25

4

Just create a new dictionary with the modifications.

orig_dict = {'foox': 'bar', 'bazx': 'bat'}
new_dict = {key[:-1]: value for key, value in orig_dict.items()}

answered Aug 11 '16 at 19:25

Morgan Thrapp

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Alexander · Accepted Answer · 2016-08-11T19:35:19.527

You should not change a mutable object such as a list or dictionary while iterating over its contents, so you are best of creating a new dictionary modifying the relevant keys where necessary. This uses a ternary to truncate the key by one character if it ends in a period ('.'), otherwise use the original key.

my_dictionary = {key[:-1] if key[-1] == '.' else key: value
                 for key, value in my_dictionary.iteritems()}  # Python 2

The new dictionary is reassigned to the old variable name my_dictionary.

score 1 · Answer 3 · answered Aug 11 '16 at 19:27

1

get each key , make new key with last . removed, then transfer data and delete that dict.

for info in dict:
  if info[-1]=='.':
    dict[info[:-1]] = dict[info]
    del dict[info]

answered Aug 11 '16 at 19:27

harshil9968

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score 0 · Answer 4 · answered Aug 11 '16 at 19:29

0

Morgan Thrapp's answer was bang on. but here's a little modification

orig_dict = {key[:-1]: value for key, value in orig_dict.items()}

You don't need to create a new dict object. Just a minor clean up job.

answered Aug 11 '16 at 19:29

Ashish Padakannaya

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This should just be a comment to his answer. – chepner Aug 11 '16 at 19:29
That's true. I just did it that way to break down the steps to make it clearer for readers. – Morgan Thrapp Aug 11 '16 at 19:30
unfortunately i don't have enough reputation to comment. Making my way to the top – Ashish Padakannaya Aug 11 '16 at 19:30
This *does* create a new dict object. It just replaces the original instead of using a new variable. – user2357112 Aug 11 '16 at 19:38

How to update keys in dictionary?

4 Answers4