Shulou(Shulou.com)06/01 Report--

In this issue, the editor will bring you an example analysis of the data merging and sorting of the two queues realized by python. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.

Recently, in database learning, I have realized that large and small data processing in the database is inseparable from data algorithms. If we begin to understand some algorithms effectively, we will have a deeper understanding of some concepts in database design.

This problem begins with the merging and sorting of the data of the two queues.

The following is only hypothetical, if we get the data from the database, and it is multi-threaded, and then we need to merge the data obtained by each thread, and the query statement requires sorting, then after we get these values, how do we sort them in memory from small to large.

As shown in the figure above, if some values are obtained and these values are in two queues, the final result is to output them at once and form a sorted queue.

Here, python is used to make a merge sort output of the following two queues

Arry1_copy = arry1.copy () # generates an identical arry1 list and is ready to use it as the final output list

Every element in the list has a corner mark, starting with 0. Here, the corner mark is used as the symbol of the specified element, which can be regarded as a substitute for the pointer.

Here, queue arry2 is used as the object queue for data extraction, and the elements are extracted one by one and compared with queue 1. If the value is smaller than the value of queue 1, it is directly inserted in front of the contrast ratio of the newly joined queue until the value of queue 2 is selected.

It seems that this program can solve the problem of data reorganization between the two queues, but in fact there are many loopholes.

The problem comes, the program remains intact, directly change the number of the value of the queue, the number of data of the value of queue 1 is less than the number of queue 2, we look again, the result becomes like this.

How to solve the problem that queue 1 is smaller than the elements of queue 2? before processing, we can make a comparison between queue 1 and queue 2. If there are many elements, that is queue 1.

After modifying the program, a judgment is added that if the number of values of queue 1 is smaller than that of queue 2, then the two queues swap positions, which can solve the problem. But in fact, even after this solution, there is still a problem, because queue 2 has only one value, and in the following figure, if queue 2 has only one value, it will trigger at the end of the new queue, and a value of queue 2 will be added.

As a result, an extra 1 was reinserted once.

Modify the code here, but in fact, even so, there is still something wrong with the program

#! / usr/bin/python3

#-*-coding: utf-8-*-

Arry1 = [1]

Arry2 = [2, 7, 10, 13]

If (len (arry1) > len (arry2)):

Arry_copy = arry1.copy ()

For i in range (0jinlen (arry2)):

Init_1= 0

While init_1 < len (arry1):

If arry2 [I] < arry_ copy [init _ 1]:

Arry_copy.insert (init_1 + I, arry2 [I])

Break

Else:

Init_1 + = 1

Else:

If len (arry2)! = 1:

Arry_copy = arry_copy + arry2 [I:]

Print (arry_copy)

Else:

Arry2_copy = arry1.copy ()

Arry1_copy = arry2.copy ()

Arry1 = arry1_copy.copy ()

Arry2 = arry2_copy.copy ()

Arry_copy = arry1.copy ()

For i in range (0, len (arry2)):

Init_1 = 0

While init_1 < len (arry1):

If arry2 [I] < arry_ copy [init _ 1]:

Arry_copy.insert (init_1 + I, arry2 [I])

Break

Else:

Init_1 + = 1

Else:

If len (arry2)! = 1:

Arry_copy = arry_copy + arry2 [I:]

Print (arry_copy)

Where is the problem, if the values of the two queues are the same, or if there is data duplication? So you also need to modify the program here to find duplicates or inclusions in the two lists to avoid them.

So through an algorithm not worth mentioning Mini Program, we can see that it is not easy to get a database.

The above is the example of data merging and sorting of two queues in python shared by Xiaobian. If you happen to have similar doubts, please refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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