Datetimedatetimefromisoformat

Datetimedatetimefromisoformat refers to the class method datetime.fromisoformat in Python's standard library. Introduced in Python 3.7, it parses a string in ISO 8601 date-time format and returns a corresponding datetime object. The method is part of the datetime class, not a standalone function.

Usage and examples: The method accepts strings that include a date and time, optionally with a fractional second and a time zone offset. For example, datetime.datetime.fromisoformat('2023-07-21T15:30:45') yields a naive datetime object. A string with a numeric offset such as '2023-07-21T15:30:45+02:00' produces an aware datetime object with tzinfo set to a timezone offset of +02:00. Microseconds are supported, as in '2023-07-21T15:30:45.123456'. The string 'Z' for UTC is not directly supported by fromisoformat; replace it with '+00:00' or use an alternative parser if needed.

Return value and behavior: If the input contains a time zone offset, the resulting datetime has tzinfo set to the corresponding timezone. If no offset is present, the datetime is naive (tzinfo is None). The method strictly follows ISO 8601 formats, making it convenient for interoperable date-time data but less flexible with non-ISO variants.

Error handling: A ValueError is raised when the string is not a valid ISO 8601 date-time. A TypeError can occur if the argument is not a string. It does not parse arbitrary date formats outside ISO 8601, nor does it handle all variations of Z-based UTC notation without adjustment.

Relation to other parsing methods: For non-ISO formats, datetime.strptime can be used with an explicit format string. For date-only strings, date.fromisoformat exists. For more flexible ISO parsing, third-party libraries like dateutil can be employed.