DEV Community: Lucas de Brito Silva

Answer: How do I increase the contrast of an image in Python OpenCV

Lucas de Brito Silva — Tue, 21 Jul 2020 14:40:53 +0000

Apr 26 '18

For Python, I haven't found an OpenCV function that provides contrast. As others have suggested, there are some techniques to automatically increase contrast using a very simple formula.

In the official OpenCV docs, it is suggested that this equation can be used to apply both contrast and brightness at…

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Module, Package, Library or Framework?

Lucas de Brito Silva — Fri, 19 Jun 2020 11:34:00 +0000

Module is a file which contains various Python functions and global variables. It is simply just .py extension file which has python executable code.

Package is a collection of modules. It must contain an __init__.py file as a flag so that the python interpreter processes it as such. The __init__.py could be an empty file without causing issues.

Library is a collection of packages.

Framework is a collection of libraries. This is the architecture of the program.

Application is an application. Yah, I’m sure about this one.

Reference

https://kimconnect.com/python-module-vs-package-vs-library-vs-framework/

TRICK: Easy requirements build

Lucas de Brito Silva — Mon, 25 May 2020 03:52:00 +0000

A few days ago I was doing a project in Python and wanted to let it practice for anyone who wanted to access it, and one of the steps for that was to build the requirements.txt, that commonly loads the necessary packages to run the projects in Python and the easiest alternative is:

view the packages in the project;
select the packages after executing:

$ pip freeze

But that's not practical at all, so I looked for an alternative that would meet my need, and found a project that did just that. Its goal is generate requirements.txt based on imports in project.

To install this package, just run:

$ pip install pipreqs --user

or, if you use Python3:

$ pip3 install pipreqs --user

To build automatically your requirements.txt, just run the following command in the project directory:

$ pipreqs

$ pipreqs /project/location

And the magic will happen!!

I hope this post helped and feel free to get in touch! ;)
Thanks for reading!

This post is inspired by the following repository:

bndr / pipreqs

pipreqs - Generate pip requirements.txt file based on imports of any project. Looking for maintainers to move this project forward.

`pipreqs` - Generate requirements.txt file for any project based on imports

Installation

pip install pipreqs

Obs.: if you don't want support for jupyter notebooks, you can install pipreqs without the dependencies that give support to it. To do so, run:

pip install --no-deps pipreqs
pip install yarg==0.1.9 docopt==0.6.2

Usage

Usage
    pipreqs [options] [<path>]

Arguments:
    <path>                The path to the directory containing the application files for which a requirements file
                          should be generated (defaults to the current working directory)

Options:
    --use-local           Use ONLY local package info instead of querying PyPI
    --pypi-server <url>   Use custom PyPi server
    --proxy <url>         Use Proxy, parameter will be passed to requests library. You can also just set the
                          environments parameter in your terminal:
                          $ export HTTP_PROXY="http://10.10.1.10:3128"
                          $ export HTTPS_PROXY="https://10.10.1.10:1080"
    --debug               Print debug information
    --ignore <dirs>...    Ignore extra directories, each separated by a comma
    --no-follow-links     Do not follow symbolic links in the project
    --encoding <charset>  Use encoding

…

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Answer: matplotlib: binary heat plot

Lucas de Brito Silva — Mon, 18 May 2020 11:33:12 +0000

Feb 14 '15

You need what's known as a ListedColorMap:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl

# random data
x = np.random.random_integers(0, 1, (10, 10))

fig, ax = plt.subplots()

# define the colors
cmap = mpl.colors.ListedColormap(['r', 'k'])

# create a normalize object the describes the limits

…

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Rename and Delete files with Python

Lucas de Brito Silva — Sat, 25 Apr 2020 19:47:31 +0000

Every day I find myself in need of doing tiring jobs that can be replaced by scripts and that the computer can help me too much, so one day I thought "Okay, I got tired, from now on I refuse to do that kind of work!" and from then on things only got better.

Since college, I created a great bond with the Python programming language, and we became great friends. That way I developed a script with him that would save my life!

In my work sometimes I needed to rename files from a list or even delete them from a folder, because they were no longer useful. So my first approach was to create two functions.

The first function was to rename files, so that they had a pattern and an order, like: file_1, file_2 and so on.

The heart of this code, as you can see, is in the os.rename that renames from the old name to the new file name.
NOTE: One very cool thing is that the script renames the whole way, so it makes use of the glob.

The second problem was that I needed to delete all files that were not on a .txt list (believe me, that list was over 100 files). So I used a very similar approach, but with the use of pandas, to read the txt file, of .index to try to find the file and os.remove to remove the files outside the list. The code is shown below.

And it's because of scripts like these that I have time today to write this article for you. I hope you like it and that it helped!