Load a named standard-library module with importlib

importlib.import_module() imports a module from a string name and returns that requested module. This is useful when a program selects from a controlled dispatch table or configuration value. Here, the concrete input is the string "statistics". The returned module provides mean(), which receives [2, 4, 6]; the assertion verifies that this calculation produces 4 before the program prints two stable lines.

The example intentionally names a standard-library module, so it needs no local fixture or network access. import_module() accepts absolute names and can resolve relative names when a package anchor is supplied. It is a programmatic-import interface, not a validator for arbitrary plugin names: importing executes module-level code. An application should restrict or validate names obtained from untrusted input before importing them. The assertion establishes this one calculation in the running interpreter; it does not establish that every attribute of the imported module is suitable for an application.

The importlib package was added in Python 3.1. The documentation recommends import_module() rather than calling __import__() directly for programmatic imports. See the Python importlib documentation.

import importlib

module = importlib.import_module("statistics")
result = module.mean([2, 4, 6])

assert result == 4
print(f"module: {module.__name__}")
print(f"mean: {result}")
module: statistics
mean: 4

AI-assistance disclosure: AI helped draft this explanation and example.

Comments

Post a Comment

Popular posts from this blog

Compare Two Text Files in Python Without Modifying Them

Batu Lab Notes · Batu When comparing two versions of a configuration or notes file, “are they the same?” is only the first question. The bytes may be identical, the visible text may be equal despite different line endings, or the content may contain a real change. For small UTF-8 text files, Python’s standard library can show these distinctions without writing to either input. Quick answer For small, stable UTF-8 files, read bounded bytes, compare them first, then decode and produce a bounded unified diff. Decide explicitly whether newline differences matter. Keep both inputs read-only and review the diff for private data before sharing it. Set a limit before reading Loading an input of unknown size directly into memory is a poor default. This example checks both sizes with Path.stat() , then performs a bounded read and applies a 256 KiB limit per file. It rejects directories and other non-regular paths. If reading raises OSError , the result includes the exception ty...
Read more

Seven CSV Quality Checks to Run Before Importing Data

Batu Lab Notes · Batu A CSV file is not ready for import merely because it opens. The wrong delimiter can collapse an entire row into one column. An unexpected encoding can damage non-ASCII characters. A repeated identifier can overwrite an existing record in the destination. A short, read-only check makes these problems visible before data reaches a spreadsheet or application. Quick answer Before importing a CSV, set its encoding and delimiter, validate the exact header and every row width, distinguish empty IDs, duplicate IDs, and duplicate rows, and keep the check read-only. 1. Specify the encoding Python may open a text file with the platform’s default encoding, which can differ across machines. If the expected encoding is UTF-8, encoding="utf-8-sig" is a practical choice: it reads ordinary UTF-8 and skips an optional UTF-8 byte order mark at the start. If decoding fails, verify the source application’s export settings instead of silently trying unrelat...
Read more

Explain why SQLite transactions cannot make an HTTP call atomic

Direct answer A SQLite transaction can atomically commit database statements handled by that connection. It cannot include an HTTP service in the same commit protocol. The example commits an outbox row first, then simulates a network failure. The durable row remains pending , which is exactly the information a later delivery worker needs instead of pretending both actions succeeded or failed together. The edge case is failure after the database commit but before remote acknowledgement. Retrying then requires an idempotency design owned by the remote endpoint or a stable request key; it is not supplied by SQLite’s COMMIT . Conversely, sending the request before storing a durable intent can leave no local evidence when the process stops. This demonstration intentionally does not make an HTTP request, implement an outbox dispatcher, or prove delivery exactly once. It shows the boundary that must be designed around. Use transactions to protect the local state transition, and test remote...
Read more