Date parsing

Enables reliable conversion of formatted date strings into datetime objects for further processing.

Web scraping: extracting publication dates from HTML meta tags; Data pipelines: converting CSV date columns to datetime objects for analysis; Logging: parsing timestamps from log files into datetime objects.

Python data analysis, web backends, automation scripts, ETL pipelines

datetime.strptime(date_string, format_string)

datetime.strptime(..., ...)

date_string: str, format_string: str

• Often paired with try/except ValueError for invalid formats
• used with datetime.datetime objects
• combined with strftime for reverse formatting.

• dateutil.parser.parse (more flexible but heavier)
• pandas.to_datetime (vectorized parsing for Series)
• datetime.fromisoformat (ISO‑8601 only
• faster).

Swapping the arguments (format first, date string second) → TypeError: strptime() argument 1 must be str, not _datetime.datetime; Using incorrect format directives (e.g., %M for month instead of %m) → ValueError: time data does not match format; Passing a non‑string (e.g., datetime object) as the first argument → AttributeError: 'datetime.datetime' object has no attribute 'strptime'; Forgetting to import the datetime module → NameError: name 'datetime' is not defined; Including leading/trailing whitespace in the date string → ValueError: unconverted data remains.

datetime.strftime (formats datetime → string); dateutil.parser.parse (flexible parsing without format string); datetime.fromisoformat (ISO‑8601 only parsing).

Coming from JavaScript: assuming Date.parse works like strptime → Python requires an explicit format string; Coming from SQL: expecting %Y-%m-%d to be interpreted as a date literal → the format string must be passed as an argument and the input must be a string.

• datetime.strftime
• datetime.fromisoformat
• dateutil.parser.parse

Do not use when locale‑aware parsing is needed (e.g., month names in non‑English locales); consider babel or dateutil instead.; Performance impact is minimal for occasional calls, but parsing in tight loops can become a bottleneck; consider caching results or using vectorized libraries like pandas.; Boundary conditions: the format must match exactly, extra whitespace causes ValueError, and two‑digit years (%y) interpret 00‑68 as 2000‑2068 and 69‑99 as 1969‑1999.

Enables reliable conversion of user‑supplied date strings into datetime objects for arithmetic, storage, or display, preventing bugs caused by manual string slicing or incorrect assumptions about format.

Think of strptime as a translator that turns a date written in human language into a computer’s internal clock, but only if you hand it the exact dictionary.

The format directives follow the same specification as strftime; see the Python documentation for a full list.

Use dateutil.parser.parse for locale‑aware, flexible date parsing.