Heapy - Ordered Customisable Heaps in python

Easy to use, customisable ordered heaps in python.

Installation

pip install heaps

OR....

Just copy heap.py to your file or directory

Usage and Methods

Creation

You can create a heap from an array of nodes. A node here can be anything from what you want it to be. An integer, string, custom class, dictionary node

Empty heap

You can create an empty heap by

heap = Heap(). # Min Heap
heap = Heap(min_heap=False) # Max Heap

From Array

You can create the heap from an array in the following way:

arr = [9,0,-1,2,3,21]
min_heap = Heap.from_array(arr)
max_heap = Heap.from_array(arr, min_heap=False)

Insertion in heap

You can push elements into the heap in the following manner.

arr = [9,0,-1,2,3,21]
heap = Heap.from_array(arr, min_heap=True)
heap.insert(12)
heap.insert(120)

Top

You can get the top element from heap

arr = [9,0,-1,2,3,21]
heap = Heap.from_array(arr, min_heap=True)
heap.top()

Length of Heap

You can getlength of heap

arr = [9,0,-1,2,3,21]
heap = Heap.from_array(arr, min_heap=True)
heap.length

Pop

You can pop from heap

arr = [9,0,-1,2,3,21]
heap = Heap.from_array(arr, min_heap=True)
heap.insert(12)
heap.insert(120)
heap.pop().  # will print -1

Custom Score Heap

You can give a function in key which gives the score for that node, for example if you want your node to be a pair of (, )

counts = {'A':1, 'B' : 2, 'C':3}
heap = Heap.from_array(counts.items(), key= lambda y : y[1])
while heap.length:
  heap.pop()

Custom Comparator Heap

Like the sort function you can give comparator for the heap

    class CustomHeapNode:
        def __init__(self, score1, score2, label):
            self.s1 = score1
            self.s2 = score2
            self.label = label

        def __str__(self):
            return self.label + str(self.s1) + str(self.s2)

    def lte(A, B):
        if A.s1 == B.s1:
            if A.s2 < B.s2:
                return 1
            elif A.s2 == B.s2:
                return 0
            else:
                return -1
        elif A.s1 < B.s1:
            return 1
        else:
            return -1

    arr = [CustomHeapNode(5, 2, "A"), CustomHeapNode(6, 1, "B"),
           CustomHeapNode(3, 10, "C"), CustomHeapNode(21, 0, "D"),
           CustomHeapNode(-1, 22, "E")]
    heap = OrderedHeap.from_array(arr, comp_nodes=lte)
    sorted_arr = sorted(arr, key=lambda y: y.s2)
    sorted_arr = sorted(sorted_arr, key=lambda y: y.s1)

    heap_arr = []
    while heap.length:
        heap_arr.append(heap.pop())

    assert heap_arr == sorted_arr

Example

from heapy.heap import OrderedHeap

heap = OrderedHeap(min_heap=True)

for i in [1, 2, 3, 49, 10, 2, 1, 21, 2, 12, 12, 2, 2, 1, 2]:
    heap.insert(i)

while heap.length:
    print(heap.pop())