CODEWITHSUNDEEP
pythondictionary
someone
someone

Reputation: 15

Replace key references by corresponding values in dict values

In the following dictionary, a user can refer to a key as a variable for defining another value:

d = {'a_key': 'a_value', 'b_key': 'a_key+1'}

I have to replace these references by the corresponding values, in order to obtain this desired output:

d = {'a_key': 'a_value', 'b_key': 'a_value+1'}

I thought it would be easy, but this one drives crazy since a few hours. I got to this code:

for k in d.keys():
    print("key: " + k)
    print("value: " + d[k])
    for v in d.values():
        print("value_before: " + v)
        v = v.replace(k, d[k])
        print("value_after: " + v)
print(d)

The output is:

key: a_key
value: a_value
value_before: a_value
value_after: a_value
value_before: a_key+1
value_after: a_value+1
key: b_key
value: a_key+1        # WHY??
value_before: a_value
value_after: a_value
value_before: a_key+1
value_after: a_key+1
{'a_key': 'a_value', 'b_key': 'a_key+1'}

As we see, the first iteration seems to do the job, before it is cancelled by the second one. I just don't unserstand why. I also tried to adapt the very specific answers to that question: Replace values in dict if value of another key within a nested dict is found in value, but to no avail. I'm looking for a general answer to: how to get the desired output?

From a theoretic point of view, I would also like to understand why the "b_value" is reset to a_key+1. Thanks.

Upvotes: 0

Views: 542

Answers (1)

Alain T.
Alain T.

Reputation: 42143

The problem is that you are modifying temporary variable v but you are not placing the modified values back in the dictionary.

Try replacing : 

for v in d.values():
    v = v.replace(k, d[k])

with:

for r,v in d.items():
    d[r] = v.replace(k, d[k])

Upvotes: 1

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