Search a list of dictionaries in Python

Quick and efficient search

# Spoiler alert: the first dictionary did it!
first_match = next((d for d in list_of_dicts if d['key'] == 'value'), None)
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The above snippet combines a generator expression with next(). This efficient mechanism stops at the first match instead of searching the entire list. No match? No problem - None serves as a default return, ensuring you avoid a crash landing if there's no match.

For times when numbers matter as much as the dictionary itself, use enumerate() like so:

# Like a treasure hunt but with dictionaries
index, match = next((i, d) for i, d in enumerate(list_of_dicts) if d['key'] == 'value'), (None, None))
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If the word lambda gives you a Programmer's Rush™, here's how you can search using filter():

# filter(): for when simplicity just won't do!
matches = list(filter(lambda d: d['key'] == 'value', list_of_dicts))
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Remember: Python 3's filter() returns an iterator, so don't forget to pack it into a list().

Handling large data structures

While hunting through your data jungle, keep in mind that the size of the list and depth of the dictionaries can impact the search duration. List comprehensions and generator expressions may take longer for larger datasets. The strategy?

• Filter irrelevant entries before the search
• Try to avoid deeply nested key-value pairs
• Surprisingly, searching in large dictionaries isn't significantly delayed by a high number of keys, unless the key is deep within.

Broadening your search horizons

Skipping beyond exact matches, let's explore partial matches, multiple conditions, and the powerful regex:

# Partial match - it ain't much, but it's honest work
partial_matches = [d for d in list_of_dicts if 'partial_key' in d.get('key', '')]

# Multiple conditions - because why settle for less?
multi_matches = [d for d in list_of_dicts if d.get('key1') == 'value1' and d.get('key2') == 'value2']

# Regular expressions - (╯°□°）╯︵ ┻━┻
import re
regex_matches = [d for d in list_of_dicts if re.match(r'^value\d+$', d.get('key'))]
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Handling complex searches

Navigating more complex scenarios will make you an indispensable asset to the Python universe. Case-insensitivity? Check. Default values for absent keys? Check. Merge multiple searches? Double check. Here's how:

• For case-insensitive searches, use .lower().
• For default values, use dict.setdefault().
• To merge search results, use itertools.chain().