what is a requirements.txt file and what does it do?

A "requirements.txt" file is an important part of software projects. It contains a list of requirements that must be met before the software will function correctly, and is typically used in Python applications. As such, it is a vital part of the development process and can help make sure that the same versions of components are used throughout a project in order to avoid conflicts and ensure compatibility.

Requirements.txt files, also known as requirements files, typically contain all of the third-party packages or libraries that a project requires to run. Each time an application is launched or updated, these packages are installed from the central repository, PyPi, keeping each version in sync between all users. By doing this, developers can spend more time focusing on core features instead of worrying about package versions crashing their software due to compatibility issues. It's also useful for others opening up the project since they will know exactly what version of each package was used when developing it.

For example, if someone wants to run a simple Python program with several other packages (such as NumPy or Pandas), they would create a requirements file which would include details about each package such as its name, version number and any other dependencies it requires (if any). Then they could install these packages by running 'pip install -r requirements.txt' which would automatically download and install all of them at once so they don't have to search online for each individual one.

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