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Regular expressions in Python are patterns for finding, checking, extracting and replacing text, and they are provided by the built-in re module. re.search(r”\d+”, text) finds the first number in a string, re.findall() returns every match, and re.sub() replaces them. This guide covers every re function, the pattern syntax, groups, greedy and lazy matching, flags, lookarounds, … Read more >>
When I build a small reporting script, I often receive an unfamiliar object from a library, API response, or custom class. I need to know what that object contains before I can use it safely. Rather than guessing method names or digging through code first, I use the Python dir() function. The dir() function gives … Read more >>
When I build a small reporting script, I often need a fast way to organize related details. For example, an employee record may need a name, department, email, and monthly sales figure. Keeping those values in separate variables becomes messy quickly. That is where the Python dict() function helps. It creates a dictionary, which stores … Read more >>
When I build small automation scripts, I often create objects to hold temporary report data—such as a customer’s draft notes, an API token, or a calculated status. Once that information is no longer valid, I do not want it sitting on the object and getting reused accidentally. That is where the Python delattr() function helps. … Read more >>
A few years ago, I worked on a small signal-analysis script for a Chicago engineering team. The input data included values such as 12+5j, and the script needed to calculate magnitudes, phase angles, and combined signals. Regular integers and floats were not enough. That is where Python’s built-in complex() function becomes useful. It creates complex … Read more >>
A few years ago, I built a small reporting utility for a sales team in Austin. The team wanted to save simple calculation rules in a configuration file, such as amount * 0.08 for a commission or units * price for a revenue total. Instead of hard-coding every rule, I needed a controlled way to turn those text expressions … Read more >>
When I build small reporting tools, I often need to create the same kind of object from different inputs. One report may come from a CSV file, another from a dictionary returned by an API, and another from values entered in the terminal. Creating separate setup code outside the class gets messy fast. The Python classmethod() function … Read more >>
When I build small reporting scripts, I often need to create clean separators, checkmarks, labels, or encoded text without hard-coding every character. That is where the Python chr() function becomes useful. Give it a number, and it returns the matching character. For example, a CSV cleanup script may need to add a tab character between … Read more >>
The Python callable function, callable(obj), returns True when you can put parentheses after an object and call it, and False when you can’t. Functions, methods, lambdas and classes are callable; numbers, strings and lists aren’t: Every output on this page comes from my own runs on Python 3.12.5, with prices and fees as the sample … Read more >>
When I build small Python automation scripts, I often need to move data between two very different worlds. One side uses readable text, such as a customer name or a JSON response. The other side expects raw binary data, such as a file, an API request body, or a network message. That is where the … Read more >>