ตรึง Dependencies ด้วย requirements.txt

Your code calls libraries, and libraries change. Pinning means writing down the exact versions so today's install matches tomorrow's. 📌

In Python, a plain text file named requirements.txt lists every package your project needs, one per line. It is your install recipe.

A bare name like pandas installs the newest release, which can differ tomorrow. That silent change is how a working model suddenly breaks.

Use the == operator to lock a precise version. Now every machine installs the same code, every single time.

The pip freeze command prints every installed package with its exact version, ready to paste into your file.

Hand the file to pip and it recreates your whole setup. The -r flag means read requirements from this file.

The ~= operator allows safe patch updates but blocks breaking ones. It accepts 1.4.x but never jumps to 1.5.

The packages you list pull in their own dependencies too. Those hidden ones can shift versions and break you just as easily.

A lock file records the exact version of every package, including hidden transitive ones. pip-tools and Poetry generate these for you.

Adding a hash makes pip reject any package whose bytes do not match. It guards against tampered or swapped downloads.

Check requirements.txt into version control beside your code. Now the exact environment travels with every commit and review.

Which line guarantees the same scikit-learn version on every machine?

You learned to pin exact versions in requirements.txt, freeze and reinstall them, and lock the full tree so installs stay deterministic. 🎯