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Introduction...The main purpose of charts is to make understand data easily. "A picture is worth a thousand words" means complex ideas that cannot be expressed in words can be conveyed by a single image/chart.When drawing graphs with lot of information, a legend may be pleasing to display relevant information to improve the understanding of the data presented.How to do it..In matplotlib, legends can be presented in multiple ways. Annotations to draw attention to specific points are also useful to help the reader understand the information displayed on the graph.1. Install matplotlib by opening up the python command prompt and firing ... Read More
Introduction..One of the biggest advantage of writing an API is to extract current/live data, even when the data is rapidly changing, an API will always get up to date data. API programs will use very specific URLs to request certain information e.g. Topp 100 most played songs of 2020 in Spotify or Youtube Music. The requested data will be returned in an easily processed format, such as JSON or CSV.Python allows the user to write API calls to almost any URL you can think of. In this example I will show how to extract API results from GitHub and visualize ... Read More
Introduction..In this example, we will create a task queue that holds all the tasks to be executed and a thread pool that interacts with the queue to process its elements individually.We will begin with the question, what is a Queue?. A queue is a data structure that is a collection of different elements maintained in a very specific order. Let me explain by taking a real life example.Assume you stand in line to pay your grocery billat a grocery shop counter, (don't ask me which grocery shop)In a line of people waiting to pay their bills, you will notice the ... Read More
Problem..Assume you have a directory full of files with different formats, to search for a particular keyword.Getting ready..Install below packages.1. beautifulsoup42. python-docxHow to do it...1. Write a function to search for a string in CSV format. I will be using csv.reader module to go through the file and search for the string and return True when found else False.Exampledef csv_stringsearch(input_file, input_string): """ Function: search a string in csv files. args: input file , input string """ with open(input_file) as file: for row in csv.reader(file): for column in row: if input_string in column.lower(): return True return False2. Function to search a ... Read More
Introduction..Sometimes, the programs require optional arguments when supplied will use them else go back to default declarations. We will see in this example on how to use them.The parameters that start with dashes (--) are identified as optional, so they can be left out, and they may have default values.Parameters that don’t start with dashes are positional and are usually required, so they do not have default values.How to do it...Exampleimport argparse parser = argparse.ArgumentParser(description='Optional Argument Example') parser.add_argument('-n', '--name', metavar='name', default='World', help='Say Hello to ') args = parser.parse_args() print(f"Hello {args.name}")The “metavar” will show up in the usage to describe the ... Read More
IntroductionMatplotlib allows to add more than one plot in the same graph. In this tutorial, I will show you how to present data in the same plot, on two different axes.How to do it..1. Install matplotlib by opening up the python command prompt and firing pip install matplotlib.import matplotlib.pyplot as plt2. Prepare the data to be displayed.import matplotlib.pyplot as plt # data prep (I made up data no accuracy in these stats) mobile = ['Iphone', 'Galaxy', 'Pixel'] # Data for the mobile units sold for 4 Quaters in Million units_sold = (('2016', 12, 8, 6), ('2017', 14, 10, ... Read More
Problem..Assume you need to check the start or end of a string for a specific text patterns. The common patterns might be filename extensions but can also be anything. I will show you few methods on how you can do this.Startswith() methodA simple way to check the beginning of a string is by using startswith() method.Exampletext = "Is USA colder than Australia?" print(f"output {text.startswith('Is')}")OutputTrueExamplefilename = "Hello_world.txt" print(f"output {filename.startswith('Hello')}")OutputTrueExamplesite_url = 'https://www.something.com' print(f"output {site_url.startswith('http:')}")OutputFalseExampleprint(f"output {site_url.startswith('https:')}")OutputTrueendswith() Method.A simple way to check the ending of a string is by using endswith() method.Outputtext = "Is USA colder than Australia?" print(f"output ... Read More
ProblemYou want to search for and replace a text pattern in a string.If we have a very simple literal patterns, using the str.replace() method is an optimal solution.Exampledef sample(): yield 'Is' yield 'USA' yield 'Colder' yield 'Than' yield 'Canada?' text = ' '.join(sample()) print(f"Output {text}")OutputIs USA Colder Than Canada?Let us first see how to search a text.# search for exact text print(f"Output {text == 'USA'}")OutputFalseWe can search for the text using the basic string methods, such as str.find(), str.endswith(), str.startswith().# text start with print(f"Output {text.startswith('Is')}")OutputTrue# text ends with print(f"Output {text.startswith('Is')}")OutputTrue# search text with find print(f"Output ... Read More
Introduction...The queue module provides a first-in, first-out (FIFO), Last-in, First out (LIFO) data structure suitable for multi-threaded programming. Queues can be used to pass data or any wide range of information e.g. session details, paths, variables, .. between creator and consumer threads safely. Locking is generally handled for the caller.Note : This discussion assumes you already understand the general nature of a queue. If you do not, you may want to read some of the references before continuing.1. Let us implement a basic FIFO Queue.import queue fifo = queue.Queue() # put numbers into queue for i in range(5): fifo.put(i) ... Read More
This article is aimed at developers who want to find the largest or smallest items with Python. I will show a few methods touse and will conclude the best method for you.Method – 1: Slice approach on a ListIf you are simply trying to find the single smallest or largest item i.e N = 1, it is faster to use min() and max().Let us begin by generating some random integers.import random # Create a random list of integers random_list = random.sample(range(1, 10), 9) random_listOutput[2, 4, 5, 1, 7, 9, 6, 8, 3] FINDING THE SMALLEST & LARGEST ITEM (N=1) # ... Read More