How to Install and Import Python Modules with pip

TL;DR

Python modules let you reuse existing code instead of writing every capability from scratch. Built-in modules ship with Python, while external modules must be installed through pip before they can be imported. In a terminal, install a package with a command such as "pip3 install pandas," then access it in Python with an import statement such as "import pandas."

Transcript

Guys welcome back to 100 Days Of Code In today's video we'll talk about 'Modules' & "What is 'pip'? " Basically modules are used to borrow someone else's code Which means you can use someone else's code in your program with the help of modules We have 2 kind of 'Modules'

1. Built-in Modules And the 2nd one is External Modules which are installed us... Read More

Key Insights

• Python modules are code libraries that allow programs to use code written by other people. They reduce the need to recreate basic functionality from scratch, saving time and effort that can instead be directed toward larger projects.
• Built-in modules are included with the Python programming language and do not require separate installation. The tutorial demonstrates this with hashlib, which can be imported and used without triggering a package download.
• External modules are separately created packages that must be installed before a local Python interpreter can import them. The tutorial uses pandas, scikit-learn, and tensorflow as examples of packages obtained from the internet.
• pip is a package manager that installs requested Python packages into the interpreter. The tutorial compares it to someone who brings required household items home from the appropriate place when they are needed.
• The installation command is "pip install" followed by a package name, although the tutorial uses "pip3" on Mac and Linux and "pip" on Windows. For example, "pip3 install pandas" downloads and installs pandas.
• A package's installation name can differ from its import name. The tutorial installs scikit-learn with "pip3 install scikit-learn," but accesses the installed module in Python by writing "import sklearn."
• ModuleNotFoundError is shown when Python cannot find a requested module on the computer. Importing sklearn fails before installation, but the same import succeeds after scikit-learn and its dependencies have been installed.
• Replit is a browser-based IDE that can detect an imported external module and install it automatically. This convenience can hide the missing-module error that would appear when running the same import in a local environment without the package.

Questions & Answers

Q: What are modules in Python?

Python modules are code libraries that a programmer can use through the import keyword. They make it possible to use code written by other people instead of implementing every capability from scratch. The tutorial emphasizes that this saves time and effort, reduces opportunities for human error, and allows programmers to focus on larger projects such as machine learning programs.

Q: What is the difference between built-in and external Python modules?

Built-in modules ship with the Python programming language, so they can be imported without a separate installation. External modules are written and distributed separately, and they must be installed from the internet before a local interpreter can use them. The tutorial demonstrates hashlib as built-in and presents pandas, scikit-learn, and tensorflow as external packages.

Q: How do you install a Python package with pip?

Open a terminal and enter "pip install" followed by the package name. The tutorial uses "pip3 install pandas" to install pandas and "pip3 install scikit-learn" to install scikit-learn. It states that Mac and Linux users should use pip3, while Windows users should use pip. pip then collects, downloads, and installs the requested package.

Q: How do you import an installed Python module?

Start Python or create a Python script, then write the import keyword followed by the module name. The tutorial uses "import pandas" after installing pandas and "import sklearn" after installing scikit-learn. If the required package is available, the import completes without an error. A script can place the import statement in a file named main.py.

Q: Why does Python show ModuleNotFoundError?

Python shows ModuleNotFoundError when the requested module is not present in the current environment. In the tutorial, "import sklearn" initially produces "ModuleNotFoundError: No module named 'sklearn'" because scikit-learn has not been installed. After running "pip3 install scikit-learn" and allowing its dependencies to install, importing sklearn works without the error.

Q: Why is scikit-learn installed but sklearn imported?

The package uses different names for installation and use in Python. The tutorial runs "pip3 install scikit-learn" to obtain the package, then writes "import sklearn" inside the Python interpreter. This example shows why the exact package name used with pip may not always be identical to the module name written after the import keyword.

Q: What is the Python REPL?

REPL means Read, Evaluate, Print, Loop. It is the interactive interface displayed after starting Python from the terminal with a command such as "python3" on the demonstrated system. The tutorial uses it to test imports and a print statement, then exits it with "Exit()." For regular work, the instructor prefers executing Python scripts instead of relying on the REPL.

Q: How does Replit handle external Python modules?

Replit can detect when a program imports an external module that is not installed and then install the required package automatically. The tutorial shows this behavior with pandas and tensorflow. Because Replit handles installation for convenience, an import may succeed there even though the same code would produce an error in a local Python environment where the package has not been installed.

Summary & Key Takeaways

• Python modules are code libraries that can be used in a program through the import keyword. They help programmers avoid rebuilding basic capabilities while working on larger projects. The tutorial divides modules into two categories: built-in modules included with Python and external modules that must be obtained separately through a package manager.

• pip is Python's package manager for installing external packages from the internet. The tutorial demonstrates commands such as "pip3 install pandas" and "pip3 install scikit-learn." After installation, the corresponding modules can be imported as pandas and sklearn. Attempting to import an unavailable module produces a ModuleNotFoundError until its package is installed.

• The Python REPL provides a Read, Evaluate, Print, Loop interface for testing commands interactively, although regular programs can be placed in files such as main.py. Replit combines a browser-based IDE, shell, and console, and it can automatically detect and install packages when code imports external modules such as pandas or tensorflow.