CODEWITHSUNDEEP
pythondictionaryreplaceformatplaceholder
user1087973
user1087973

Reputation: 1118

String replace/format placeholder values in a nested python dictionary

Let's say I have a nested dictionary like this:

example_dict = {
    'key_one': '{replace_this}',
    'key_two': '{also_replace_this} lorem ipsum dolor',
    'key_three': {
        'nested_key_one': '{and_this}',
        'nested_key_two': '{replace_this}',
    },
}

What is the best way to format the placeholder string values and either return a new a dictionary or edit the existing example_dict? Also, account for any depth.

UPDATE

I tried out something else.

import json

output = json.dumps(example_dict)
output = output.format(replace_this='hello')

Although I get a KeyError on the first key it encounters from the .format() statement.

Upvotes: 2

Views: 3797

Answers (1)

huapito
huapito

Reputation: 395

You could have another dict with your variables and a function that replaces them in string values recursively

def replace_in_dict(input, variables):
    result = {}
    for key, value in input.iteritems():
        if isinstance(value, dict):
            result[key] = replace_in_dict(value, variables)
        else:
            result[key] = value % variables
    return result


example_dict = {
    'key_one': '%(replace_this)s',
    'key_two': '%(also_replace_this)s lorem ipsum dolor',
    'key_three': {
        'nested_key_one': '%(and_this)s',
        'nested_key_two': '%(replace_this)s',
    },
}

variables = {
    "replace_this": "my first value",
    "also_replace_this": "this is another value",
    "and_this": "also this",
    "this_is_not_replaced": "im not here"
}

print replace_in_dict(example_dict, variables)
# returns {'key_two': 'this is another value lorem ipsum dolor',
#'key_one': 'my first value',
# 'key_three': {'nested_key_two': 'my first value', 'nested_key_one': 'also this'}}

Upvotes: 3

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