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Articles by Kiran P
Page 11 of 11
How to unpack using star expression in Python?
IntroductionOne of the basic limitation of unpacking is that you must know the length of the sequences you are unpacking in advance.How to do it..random_numbers = [0, 1, 5, 9, 17, 12, 7, 10, 3, 2] random_numbers_descending = sorted(random_numbers, reverse=True) print(f"Output *** {random_numbers_descending}")Output*** [17, 12, 10, 9, 7, 5, 3, 2, 1, 0]If I now wanted to find out the largest and second largest from the numbers, we will get an exception "too many values to unpack".print(f"Output *** Getting the largest and second largest") largest, second_largest = random_numbers_descendingOutput*** Getting the largest and second largest--------------------------------------------------------------------------- ValueError Traceback (most recent call last) ...
Read MoreHow to perform Calculations with Dictionaries in Python?
ProblemYou want to perform various calculations (e.g., minimum value, maximum value, sorting, etc.) on a dictionary of data.Solution.We will create a dictionary with tennis players and their grandslam titles.PlayerTitles = { 'Federer': 20, 'Nadal': 20, 'Djokovic': 17, 'Murray': 3, 'Theim' : 1, 'Zverev': 0 }1.We have a dictionary with player names and the grandslam titles won by each player. Now let us try to find out the player with least number of titles#type(PlayerTitles) print(f"Output *** The minimum value in the dictionary is {min(PlayerTitles)} ")Output*** The minimum value in the dictionary is Djokovic2. This is ...
Read MoreHow to compare two DataFrames in Python Pandas with missing values
IntroductionPandas uses the NumPy NaN (np.nan) object to represent a missing value. This Numpy NaN value has some interesting mathematical properties. For example, it is not equal to itself. However, Python None object evaluates as True when compared to itself.How to do it..Let us see some examples to understand how np.nan behaves.import pandas as pd import numpy as np # Python None Object compared against self. print(f"Output *** {None == None} ")Output*** True# Numpy nan compared against self. print(f"Output *** {np.nan == np.nan} ")Output*** False# Is nan > 10 or 1000 ? print(f"Output *** {np.nan > ...
Read MoreHow to use the Subprocess Module in Python?
Understanding Process -When you code and execute a program on Windows, MAC or Linux, your Operating System creates a process(single).It uses system resources like CPU, RAM, Disk space and also data structures in the operating system’s kernel. A process is isolated from other processes—it can’t see what other processes are doing or interfere with them.Note: This code has to be run on Linux like sytems. When executed on windows might throw exceptions.Goals of Operating System -The main twin goals of OS are to spread the work of the process fairly and be responsive to the user. These are acheived by ...
Read MoreHow to process iterators in parallel using ZIP
IntroductionList comprehensions make it easy to take a source list and get a derived list by applying an expression. For example, say that I want to multiply each element in a list with 5. Here, I do this by using a simple for loop.a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] multiply_by_5 = [] for x in a: multiply_by_5.append(x*5) print(f"Output *** {multiply_by_5}")Output*** [5, 10, 15, 20, 25, 30, 35, 40, 45, 50]With a list comprehension, I can achieve the same outcome by specifying the expression and the input sequence to loop over.# List comprehension multiply_by_5 ...
Read MoreHow to process excel files data in chunks with Python?
IntroductionIt seems that the world is ruled by Excel. I've been surprised in my data engineering work to see how many of my colleagues are using Excel as a critical tool for making decisions. While I'm not a big fan of MS Office and their excel spread sheets, i will still show you a neat trick to handle large excel spread sheets effectively.How to do it..Before we jump into the program directly, let us understand few basics on dealing excel spreadsheets with Pandas.1. Installation. Go ahead and install openpyxl and xlwt. If you are unsure if it is installed or ...
Read MoreHow to Parse HTML pages to fetch HTML tables with Python?
ProblemYou need to extract the HTML tables from a web page.IntroductionThe internet, and the World Wide Web (WWW), is the most prominent source of information today. There is so much information out there, it is just very hard to choose the content from so many options. Most of that information is retrievable through HTTP.But we can also perform these operations programmatically to retrieve and process information automatically.Python allows us to do this using its standard library an HTTP client, but the requests module helps in obtaining web pages information very easy.In this post, we will see how to parse through ...
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