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London | 25-SDC-July | Andrei Filippov | Sprint 2 | Implement an LRU cache in Python #29

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London | 25-SDC-July | Andrei Filippov | Sprint 2 | Implement an LRU cache in Python #29

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d41563f
done lru caching
Droid-An Oct 13, 2025
28212f9
Refactor set method to improve existing cache handling
Droid-An Jan 27, 2026
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22 changes: 22 additions & 0 deletions Sprint-2/implement_lru_cache/lru_cache.py
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Original file line number Diff line number Diff line change
@@ -0,0 +1,22 @@
from collections import OrderedDict


class LruCache:
def __init__(self, limit):
if limit < 1:
raise ValueError("Limit cannot be less than 1")
self.limit = limit
self.storage = OrderedDict()

def set(self, key, value):
if len(self.storage) < self.limit:
self.storage[key] = value
else:
self.storage.popitem(last=False)
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@OracPrime OracPrime Jan 26, 2026

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If the cache is full and you set something which is already in the cache, what happens?

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@Droid-An Droid-An Jan 27, 2026

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It would remove the least recently used item and update the value of the existing one. I fixed this by adding a membership check: if the item is already in the cache, it’s moved to the end and its value is updated.

self.storage[key] = value

def get(self, key):
if key in self.storage:
self.storage.move_to_end(key)
return self.storage[key]
return None