Dictionaries & sets
Key–value maps, uniqueness, counting, grouping, and fast lookups.
Filter Dictionary Keys by Prefix in Python
Use a dict comprehension to build a new dictionary containing only keys that start with a given prefix.
def filter_dict_keys(data, prefix="temp_"):
"""
Filter a dictionary by keeping only keys that start with a given prefix.
Uses a dict comprehension to build a new dictionary.
"""
if not isinstance(data, dict):
raise ValueError("data must be a dictionary")
return {key: value for key, valu…How to Filter a Dictionary by Predicate on Values in Python
This code defines a reusable function that builds a new dictionary containing only the items whose values satisfy a given predicate function.
def filter_dict_by_predicate(d, predicate):
"""Return a new dict with only items whose value passes the predicate."""
return {k: v for k, v in d.items() if predicate(v)}
if __name__ == "__main__":
scores = {"Alice": 85, "Bob": 42, "Charlie": 91, "Diana": 60}
# Keep only values greater than or equal t…How to Remove Banned Words from a Set in Python
Filter a vocabulary set by removing banned words using the .difference() method.
vocabulary = {"apple", "banana", "cherry", "date", "elderberry"}
banned_words = {"banana", "date", "fig"}
# Remove banned words using set difference
allowed_words = vocabulary.difference(banned_words)
print("Original vocabulary:", sorted(vocabulary))
print("Banned words:", sorted(banned_words))
print("Allowed words …Browse by section
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Dictionaries & sets — Python code examples
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