How to Efficiently Find Specific Key-Value Pairs in a List of Python Dictionaries?

Searching for Specific Dictionnaire Key-Values in Python

Given a list of dictionaries, it is common to search for specific key-values to retrieve the corresponding dictionary. For instance, consider the following list:

[
  { "name": "Tom", "age": 10 },
  { "name": "Mark", "age": 5 },
  { "name": "Pam", "age": 7 }
]

To find the dictionary with the name "Pam", we can use a generator expression:

dicts = [
  { "name": "Tom", "age": 10 },
  { "name": "Mark", "age": 5 },
  { "name": "Pam", "age": 7 }
]

matching_dict = next(item for item in dicts if item["name"] == "Pam")

The next() function returns the first item in the generator, which is the dictionary with the name "Pam". Using a generator expression allows for efficient iteration without storing all the results in memory.

For cases where the item may not exist, we can provide a default value by using the next() function with a parameter:

matching_dict = next((item for item in dicts if item["name"] == "Pam"), None)

Alternatively, we can find the index of the matching item using enumeration:

matching_index = next((i for i, item in enumerate(dicts) if item["name"] == "Pam"), None)

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