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Push and Pop from Heap

Zero-dependency Python snippets for pushing and popping from a heap using the standard library heapq module.

3 snippets available in this sub-category.

Simple

Push and pop separately

heap heapq push pop min-heap data-structures

Add and remove elements from a min-heap

import heapq

heap = [2, 3, 5]
heapq.heapify(heap)
heapq.heappush(heap, 1)
print(heap)  # [1, 2, 5, 3]
smallest = heapq.heappop(heap)
print(smallest)  # 1
print(heap)  # [2, 3, 5]

Notes

  • heappush() adds, heappop() removes smallest

Complex

heappushpop: push then pop (efficient)

heap heapq heappushpop efficient data-structures

Push new item, then pop and return smallest (single operation)

import heapq

heap = [2, 3, 5]
heapq.heapify(heap)
result = heapq.heappushpop(heap, 1)
print(result)  # 1
print(heap)  # [2, 3, 5]

result2 = heapq.heappushpop(heap, 4)
print(result2)  # 2
print(heap)  # [3, 4, 5]

Notes

  • More efficient than separate push and pop if you always want to pop after push
  • If new item is smaller than smallest, it is returned and not added

heapreplace: pop then push (always replaces)

heap heapq heapreplace replace data-structures

Pop and return smallest, then push new item (single operation)

import heapq

heap = [2, 3, 5]
heapq.heapify(heap)
result = heapq.heapreplace(heap, 1)
print(result)  # 2 (popped)
print(heap)  # [1, 3, 5]

Notes

  • Always pops and pushes, even if new item is smaller
  • Raises IndexError if heap is empty

🔗 Cross Reference

🏷️ Tags

heap, heapq, push, pop, heappushpop, heapreplace, data-structures

📝 Notes

  • Use heappushpop() for efficient push-then-pop
  • Use heapreplace() to always replace smallest