How to concatenate 2 sorted arrays in Python using heapq?

In this section, we will see how two sorted lists can be combined using the heapq module in Python. For example, if list1 = [10, 20, 30, 40] and list2 = [100, 200, 300, 400, 500], then after concatenation it will return list3 = [10, 20, 30, 40, 100, 200, 300 , 400, 500]

We will use the heapq module to accomplish this task. This module comes with Python as a standard library module. Therefore, we must import it before using it.

 import heapq 

The heapq module has some properties. It’s like below &

heapq.heapify method (repeatable)

It is used to transform an iterative dataset into a heap data structure.

The heapq.heappush method (heap, item)

This method is used to insert an item into the heap. Then copy the entire heap structure again.

The heapq.heappop method (heap)

This method is used to return and remove an item from the top of the heap and perform heapify on the rest.

The heapq.heappushpop method (heap, element)

This method is used to insert and paste an element into one statement.

The heapq.heapreplace method (heap, element)

This method is used to insert and paste an element into a single statement. It removes an element from the heap root, then inserts the element into the heap.

The heapq.nlargest (n, iterable, key = none) method

This method is used to return the n largest element from heap.

Method heapq.nsmallest (n, repeatable, key = None)

This method is used to return the n smallest element from the heap.

Code example < / h2>

 import heapq first_list = [45, 12, 63, 95, 74, 21, 20, 15, 36] second_list = [42, 13, 69, 54, 15] firs t_list = sorted (first_list) second_list = sorted (second_list) print (’First sorted list:’ + str (first_list)) print (’Second sorted list:’ + str (second_list)) final_list = list (heapq.merge (first_list, second_list)) print (’The final list:’ + str (final_list)) 

Output

 First sorted list: [12, 15, 20, 21, 36, 45, 63, 74, 95] Second sorted list: [13, 15, 42, 54, 69] The final list: [12, 13, 15, 15, 20, 21, 36, 42, 45, 54, 63, 69, 74, 95] 

How to concatenate 2 sorted arrays in Python using heapq? import heapq: Questions

How to concatenate 2 sorted arrays in Python using heapq? insert: Questions

from argparse import ArgumentParser

parser = ArgumentParser(description="test")

parser.add_argument("-g", choices=["a", "b", "g", "d", "e"], default="a",
    help="Some option, where
"
         " a = alpha
"
         " b = beta
"
         " g = gamma
"
         " d = delta
"
         " e = epsilon")

parser.parse_args()

~/Downloads:52$ python2.7 x.py -h
usage: x.py [-h] [-g {a,b,g,d,e}]

test

optional arguments:
  -h, --help      show this help message and exit
  -g {a,b,g,d,e}  Some option, where a = alpha b = beta g = gamma d = delta e
                  = epsilon

from argparse import RawTextHelpFormatter
parser = ArgumentParser(description="test", formatter_class=RawTextHelpFormatter)

>>> x = []
>>> x = x + [1]
>>> x = x + [2]
>>> x = x + [3]
>>> x
[1, 2, 3]

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