Use list of indices to manipulate a nested dictionary

Question

I'm trying to perform operations on a nested dictionary (data retrieved from a yaml file):

data = {'services': {'web': {'name': 'x'}}, 'networks': {'prod': 'value'}}

I'm trying to modify the above using the inputs like:

{'services.web.name': 'new'}

I converted the above to a list of indices ['services', 'web', 'name']. But I'm not able to/not sure how to perform the below operation in a loop:

data['services']['web']['name'] = new

That way I can modify dict the data. There are other values I plan to change in the above dictionary (it is extensive one) so I need a solution that works in cases where I have to change, EG:

data['services2']['web2']['networks']['local'].

Is there a easy way to do this? Any help is appreciated.

Julien Palard · Accepted Answer · 2016-06-06 15:12:03Z

1

You may iterate over the keys while moving a reference:

data = {'networks': {'prod': 'value'}, 'services': {'web': {'name': 'x'}}}
modification = {'services.web.name': 'new'}

for key, value in modification.items():
    keyparts = key.split('.')
    to_modify = data
    for keypart in keyparts[:-1]:
        to_modify = to_modify[keypart]
    to_modify[keyparts[-1]] = value

print(data)

Giving:

{'networks': {'prod': 'value'}, 'services': {'web': {'name': 'new'}}}

answered Jun 6, 2016 at 15:12

Julien Palard

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1 Comment

anushjay Over a year ago

Awesome. I was able to get it working with some modifications! Appreciate the help.

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