What is the requirements.txt file?

requirements.txt is a text file that lists the packages required for a Python project. It is used to specify the package dependencies for a project so that users can install all the required packages using a single command.

How to create requirements.txt?

To create a requirements.txt file for a Python project, you can use the following steps:

• Make sure you have a virtual environment set up for your project. This will allow you to install the required packages in an isolated environment, which can be helpful when you have multiple projects with different package requirements. You can follow my article on creating a virtual environment blog mentioned below.

Creating Python Virtual Environment in Linux

• Activate your virtual environment:

$ source env/bin/activate

• Install the required packages using pip, the package manager for Python. For example, to install the requests and numpy packages, you can run:

$ pip install requests numpy

• Once you have installed the required packages, you can create a requirements.txt file by running:

$ pip freeze > requirements.txt

This will create a requirements.txt file in the current directory, which will contain a list of all the packages and their respective versions that are installed in your virtual environment.

• You can then commit the requirements.txt file to version control and share it with others so that they can easily install the required packages for your project.

$ git add requirements.txt
$ git commit -m "Add requirements.txt"

Installing packages from requirements.txt

You can also use the requirements.txt file to install the required packages in another environment. To do this, activate your virtual environment, then run the:

$ pip install -r requirements.txt

This will install all the packages listed in the requirements.txt file.

You can also specify a specific version of a package in the requirements.txt file. For example:

requests==2.24.0
numpy==1.19.2

This will install the specific versions of the requests and numpy packages that are specified in the file.

It’s a good idea to regularly update the requirements.txt file to include the latest versions of the packages that your project depends on. You can do this by running pip freeze > requirements.txt again after you have updated your packages.