Config Files with configparser

configparser is Python's standard-library tool for reading and writing INI files — plain-text configuration made of [sections] and key = value pairs — so you can keep settings out of your code and edit them by hand.

Learn Config Files with configparser in our free Python course — an interactive lesson with runnable examples, a practice exercise and a quick reference.

Part of the free Python course at LearnCodingFast — hands-on lessons with examples you run in your browser, plus practice exercises and a quick quiz.

Hard-coding hosts, ports, and feature flags into your program means editing source every time something changes. A config file lets non-programmers tweak settings safely, and configparser makes reading them a one-liner.

An INI file groups settings into [sections] , each holding key = value lines. Create a ConfigParser , feed it the text (here with read_string ; from a real file you'd use config.read("app.ini") ), then access values like a nested dictionary:

Access is dictionary-style: config["section"]["key"] . Every value comes back as a string — converting to other types is the next step.

Because INI values are text, config["features"]["dark_mode"] is the string "true" , not a boolean. The typed getters convert for you — and getboolean cleverly understands many spellings of true and false:

Notice getint("server", "port") returns the integer 8080 , while the raw config["server"]["port"] is the string "8080" . Always use the typed getter when you need a real number or boolean.

Real config files don't always have every key. The fallback argument supplies a value when a key is missing, and the special [DEFAULT] section provides shared defaults that every section inherits:

configparser also writes INI. Assign a dictionary to each section, then call config.write(file) . To a real file you'd open it in text mode; here we write into an in-memory StringIO so it runs anywhere and we can print the result:

INI is great for simple, hand-edited settings — but it isn't the only option. Each format has a sweet spot:

Complete the code to read typed values from the config. Replace each ___ , then run it.

❌ Comparing a string value as if it were a bool

✅ Use the typed getter so "false" becomes the boolean False :

✅ Provide a fallback: config.getint("server", "port", fallback=8080) .

✅ Store values as strings: — and convert back with getint on read.

Build a config in code, write it to a StringIO buffer, then read that text back into a fresh parser and pull out typed values — proving a full write-then-read cycle.

Lesson complete — your settings live outside your code now!

You can read INI files with read_string and read , pull typed values with getint / getfloat / getboolean , lean on [DEFAULT] and fallback , write configs back out, and choose the right format for the job. Clean configuration is a hallmark of professional code.

🚀 Up next: Checkpoint — OOP & Standard Library — put it all together.

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