Python code that calculates with calendar dates or clock times can keep those values as objects until it needs display text. The built-in datetime module provides the types and operations for that work. In this piece, I’ll show you how…
A loop that builds a list from changed input values can leave you wondering whether there is a more direct way to write it. A Python list comprehension builds a new list by applying an expression to items from an…
To process a Python list one value at a time, your code needs a loop that visits its items. A for loop does that by assigning each item to a loop variable in list order. In this piece, I’ll show…
When a Python program needs settings that vary between machines, keeping those values out of its source code lets you change configuration separately. Environment variables are named text values supplied to a running process, and Python reads them through os.environ.…
When a Python calculation needs the area under a function, an antiderivative may not be useful. scipy.integrate.quad estimates the definite integral of a one-variable function and returns the estimate with an error estimate. I’ll show how to pass a callable…
A list of product pages can be hard to work with when the details you need are mixed into HTML. Beautiful Soup turns HTML into a structure your Python code can search, while Requests fetches the page. I’ll show how…
Ordering a list of scores or names in Python doesn’t require writing your own sorting routine. The built-in sorted() returns a new list of the items in order and leaves the original unchanged. I’ll walk you through sorting in either…
Fitting a line to data points means finding the slope and intercept that make the line’s errors as small as possible. SciPy’s minimize function searches for those values, starting from a guess you give it. The example writes the error…
Scientific calculations in Python, such as estimating an integral or finding a minimum, lead you to SciPy. It’s a free library of numerical algorithms that works on the arrays NumPy provides. I’ll map SciPy’s subpackages to the calculations they handle,…
Putting a Python list in the opposite order can mean changing the list itself or making a reversed copy. The reverse() method changes the list in place, while a slice with a step of -1 gives you a reversed copy…