7.6. Datetime Parse

• Parsing - analyze (a sentence) into its parts and describe their syntactic roles.

7.6.1. Parsing dates

>>> from datetime import datetime

Datetime parsing from string:

>>> x = '1961-04-12 06:07'
>>>
>>> datetime.strptime(x, '%Y-%m-%d %H:%M')
datetime.datetime(1961, 4, 12, 6, 7)

7.6.2. Leading Zero

Mind that while parsing dates without leading zero, you do not use %#H or %-H as it was for formatting. One should simply use %H to capture hour:

>>> x = '1961-04-12 6:07'
>>>
>>> datetime.strptime(x, '%Y-%m-%d %H:%M')
datetime.datetime(1961, 4, 12, 6, 7)

7.6.3. String Fitting

If there are any other characters in the string, such as commas, brackets spaces, colons, dashes etc, they should be reflected in the format string.

>>> x = 'Apr 12th, 1961 6:07 am'
>>>
>>> datetime.strptime(x, '%b %dth, %Y %I:%M %p')
datetime.datetime(1961, 4, 12, 6, 7)

>>> x = '12 April 1961 at 6:07 am'
>>>
>>> datetime.strptime(x, '%d %B %Y at %I:%M %p')
datetime.datetime(1961, 4, 12, 6, 7)

Omitting any of those values will result with an error:

>>> x = '12 April 1961 at 6:07 am'
>>>
>>> datetime.strptime(x, '%d %B %Y %I:%M %p')
Traceback (most recent call last):
ValueError: time data '12 April 1961 at 6:07 am' does not match format '%d %B %Y %I:%M %p'

7.6.4. Time Zone

• More information in Datetime Timezone

>>> x = '12 April 1961 6:07 UTC'
>>>
>>> datetime.strptime(x, '%d %B %Y %H:%M %Z')
datetime.datetime(1961, 4, 12, 6, 7)

>>> x = '1961-04-12 6:07 local'
>>>
>>> datetime.strptime(x, '%Y-%m-%d %H:%M')
Traceback (most recent call last):
ValueError: unconverted data remains:  local

>>> x = '1961-04-12 6:07 local'
>>>
>>> datetime.strptime(x, '%Y-%m-%d %H:%M %Z')
Traceback (most recent call last):
ValueError: time data '1961-04-12 6:07 local' does not match format '%Y-%m-%d %H:%M %Z'

>>> x = '1961-04-12 6:07 local'
>>>
>>> datetime.strptime(x, '%Y-%m-%d %H:%M local')
datetime.datetime(1961, 4, 12, 6, 7)

7.6.5. Assignments

# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Datetime Parse US
# - Difficulty: easy
# - Lines: 1
# - Minutes: 3

# %% English
# 1. Define `result: datetime` with parsed date `DATA`
# 2. Run doctests - all must succeed

# %% Polish
# 1. Zdefiniuj `result: datetime` ze sparsowaną datą `DATA`
# 2. Uruchom doctesty - wszystkie muszą się powieść

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 9), \
'Python 3.9+ required'

>>> assert result is not Ellipsis, \
'Assign result to variable: `result`'
>>> assert type(result) is datetime, \
'Variable `result` has invalid type, must be a datetime'

>>> result
datetime.datetime(1969, 7, 21, 0, 0)
"""

from datetime import datetime


DATA = 'July 21, 1969'

# DATA from US long format
# type: datetime
result = ...

# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Datetime Parse Ordinals
# - Difficulty: easy
# - Lines: 1
# - Minutes: 3

# %% English
# 1. Define `result: datetime` with parsed date `DATA`
# 2. Run doctests - all must succeed

# %% Polish
# 1. Zdefiniuj `result: datetime` ze sparsowaną datą `DATA`
# 2. Uruchom doctesty - wszystkie muszą się powieść

# %% Hints
# - `%dst`

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 9), \
'Python 3.9+ required'

>>> assert result is not Ellipsis, \
'Assign result to variable: `result`'
>>> assert type(result) is datetime, \
'Variable `result` has invalid type, must be a datetime'

>>> result
datetime.datetime(1969, 7, 21, 0, 0)
"""

from datetime import datetime


DATA = 'July 21st, 1969'

# DATA from long US format with ordinals
# type: datetime
result = ...

# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Datetime Parse List
# - Difficulty: medium
# - Lines: 8
# - Minutes: 3

# %% English
# 1. Define `result: list[datetime]` with parsed `DATA` dates
# 2. Run doctests - all must succeed

# %% Polish
# 1. Zdefiniuj `result: list[datetime]` ze sparsowanymi datami `DATA`
# 2. Uruchom doctesty - wszystkie muszą się powieść

# %% Hints
# - `for ... in`
# - `try ... except`
# - `dt.strptime()`
# - `list.append()`

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 9), \
'Python 3.9+ required'

>>> from pprint import pprint
>>> result = list(result)

>>> assert result is not Ellipsis, \
'Assign result to variable: `result`'
>>> assert type(result) is list, \
'Variable `result` has invalid type, must be a list'
>>> assert all(type(element) is datetime for element in result), \
'All elements in `result` must be a datetime'

>>> pprint(result, width=30)
[datetime.datetime(1969, 7, 21, 0, 0),
 datetime.datetime(1969, 7, 22, 0, 0)]
"""

from datetime import date, datetime


DATA = [
    'July 21st, 1969',
    'July 22nd, 1969',
]

# parsed DATA
# type: list[date]
result = ...

# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Datetime Parse Many
# - Difficulty: medium
# - Lines: 7
# - Minutes: 5

# %% English
# 1. Define `result: list[datetime]` with parsed `DATA` dates
# 2. Run doctests - all must succeed

# %% Polish
# 1. Zdefiniuj `result: list[datetime]` ze sparsowanymi datami `DATA`
# 2. Uruchom doctesty - wszystkie muszą się powieść

# %% Hints
# - `for ... in`
# - nested `try ... except`
# - `FORMATS = []`
# - `for fmt in FORMATS`
# - helper function

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 9), \
'Python 3.9+ required'

>>> assert result is not Ellipsis, \
'Assign result to variable: `result`'
>>> result = list(result)
>>> assert type(result) is list, \
'Variable `result` has invalid type, must be a list'
>>> assert all(type(element) is datetime for element in result), \
'All elements in `result` must be a datetime'

>>> result  # doctest: +NORMALIZE_WHITESPACE
[datetime.datetime(1969, 7, 21, 0, 0),
 datetime.datetime(1969, 7, 22, 0, 0),
 datetime.datetime(1969, 7, 23, 0, 0),
 datetime.datetime(1969, 7, 24, 0, 0)]
"""

from datetime import datetime, date


DATA = [
    'July 21st, 1969',
    'July 22nd, 1969',
    'July 23rd, 1969',
    'July 24th, 1969',
]

FORMATS = [
    '%B %dst, %Y',
    '%B %dnd, %Y',
    '%B %drd, %Y',
    '%B %dth, %Y',
]


# DATA elements in datetime format
# type: list[date]
result = ...