Help text produced by argparse often contains code fragments, such as file names, command lines and accepted values. Written in a sentence they blend into the surrounding words, so it...

A match statement can compare a value against number literals, and negative numbers have always been accepted, so case -1: is valid. A leading plus sign was not. Writing case...

The array module stores numbers in a fixed C type rather than as individual Python objects. The type code chosen when the array is created determines how many bytes each...

A task group runs several coroutines together and waits for all of them to finish. Sometimes that is more work than necessary. When a group asks several sources for the...

Decoding JSON produces Python objects chosen by the json module, and every JSON array becomes a list. That is a reasonable default, but a list is mutable and therefore cannot...

Many functions take an optional argument and need to know whether the caller supplied it. The simplest way is to give the argument a default of None and check for...

A command-line tool built with argparse rejects invalid values and lists the accepted ones, leaving users to spot typos themselves. Python 3.14 introduced suggestions for likely intended values, but enabling...

A bytearray can be modified after it is created, so it is a convenient place to collect data piece by piece. When the data is complete, it usually has to...

When an attribute lookup fails, Python tries to help by naming a likely candidate. The suggestion appears at the end of the error message as a "Did you mean" clause...

When strptime parses a string, any components not specified in the format are filled in using default values. A format without a year produces a date in 1900, which is...