strpdatetime

A replacement for datetime.datetime.strptime with super powers. strpdatetime is a drop-in replacement for datetime.datetime.strptime that adds a simplified regex-like syntax for finding and extracting date and time information from strings.

Why this package?

A common use case is parsing date/time information from strings, for example filenames with the date and time embedded in them. The standard library's datetime.datetime.strptime works well if the string perfectly matches the format string, but does not work if the string contains additional characters. For example, datetime.datetime.strptime("IMG_1234_2022_11_20.jpeg", "%Y_%m_%d") will fail with ValueError: time data 'IMG_1234_2022_11_20.jpeg' does not match format '%Y_%m_%d'. To use datetime.datetime.strptime in this case, you would need to first parse the string to remove the extra characters.

Third-party packages such as dateutil and datefinder are more flexible but still fail to find the date in the above example and other common filename date/time formats.

strpdatetime can find the date in the above example using strpdatetime("IMG_1234_2022_11_20.jpeg", "^IMG_*_%Y_%m_%d")

Installation

pip install strpdatetime

To install from source:

• Clone the repository
• Change to the project directory
• Install uv: curl -LsSf https://astral.sh/uv/install.sh | sh
• Create the virtual environment: uv venv or uv venv --python 3.13 to specify a specific version
• Activate the virtual environment: source .venv/bin/activate
• Install package dependencies: uv pip install -r pyproject.toml --extra dev

Source Code

The source code is available on GitHub.

Usage

>>> import datetime
>>> from strpdatetime import strpdatetime
>>> dt = strpdatetime("IMG_1234_2022_11_20.jpeg","^IMG_*_%Y_%m_%d.*")
>>> assert dt == datetime.datetime(2022,11,20)
>>>

Syntax

In addition to the standard strptime format codes, strpdatetime supports the following:

• *: Match any number of characters
• ^: Match the beginning of the string
• $: Match the end of the string
• {n}: Match exactly n characters
• {n,}: Match at least n characters
• {n,m}: Match at least n characters and at most m characters
• In addition to %% for a literal %, the following format codes are supported: %^, %$, %*, %|, %{, %} for ^, $, *, |, {, } respectively
• |: join multiple format codes; each code is tried in order until one matches
• Unlike the standard library, the leading zero is not optional for %d, %m, %H, %I, %M, %S, %j, %U, %W, and %V
• For optional leading zero, use %-d, %-m, %-H, %-I, %-M, %-S, %-j, %-U, %-W, and %-V

Examples

>>> from strpdatetime import strpdatetime
>>> strpdatetime("IMG_1234_2022_11_20.jpg","^IMG_{4}_%Y_%m_%d")
datetime.datetime(2022, 11, 20, 0, 0)
>>> strpdatetime("IMG_1234_2022_11_20.jpg","IMG_*_%Y_%m_%d")
datetime.datetime(2022, 11, 20, 0, 0)
>>> strpdatetime("1234_05_06_2022_11_20","%Y_%m_%d$")
datetime.datetime(2022, 11, 20, 0, 0)
>>> strpdatetime("1234_05_06_2022_11_20","IMG_*_%Y_%m_%d|%Y_%m_%d$")
datetime.datetime(2022, 11, 20, 0, 0)
>>>

Command Line

strpdatetime includes a very simple command line interface. It can be used to test the regex-like syntax. Use python -m strpdatetime --help for more information.

python -m strpdatetime "^IMG_*_%Y_%m_%d|IMG{4}_%Y-%m-%d-%H%M%S" *.jpg
IMG1234_2022-11-20-063400.jpg, 2022-11-20T06:34:00
IMG_1234_2022_11_21.jpg, 2022-11-21T00:00:00
time data 'IMG_2132.jpg' does not match format '^IMG_*_%Y_%m_%d|IMG{4}_%Y-%m-%d-%H%M%S'
IMG_2132.jpg,
IMG_5678_2022_11_20.jpg, 2022-11-20T00:00:00

License

To ensure backwards compatibility with the Python standard library, strpdatetime makes use of original code from the standard library and is thus licensed under the Python Software Foundation License, just as Python itself is.

Contributing

Contributions of all kinds are welcome! Please open an issue or pull request on GitHub.