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

8.9.1. 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)

8.9.2. 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)

8.9.3. 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'

8.9.4. 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)

8.9.5. Assignments

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

# %% 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

# %% 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

# %% Expected
# >>> result
# datetime.datetime(1969, 7, 21, 0, 0)

# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0

>>> assert sys.version_info >= (3, 9), \
'Python has an is invalid version; expected: `3.9` or newer.'

>>> assert 'result' in globals(), \
'Variable `result` is not defined; assign result of your program to it.'

>>> assert result is not Ellipsis, \
'Variable `result` has an invalid value; assign result of your program to it.'

>>> assert type(result) is datetime, \
'Variable `result` has an invalid type; expected: `datetime`.'

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

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

# %% Imports
from datetime import datetime

# %% Types
result: datetime

# %% Data
DATA = 'July 21, 1969'

# %% Result
result = ...


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

# %% 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

# %% 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

# %% Expected
# >>> result
# datetime.datetime(1969, 7, 21, 0, 0)

# %% Hints
# - `%dst`

# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0

>>> assert sys.version_info >= (3, 9), \
'Python has an is invalid version; expected: `3.9` or newer.'

>>> assert 'result' in globals(), \
'Variable `result` is not defined; assign result of your program to it.'

>>> assert result is not Ellipsis, \
'Variable `result` has an invalid value; assign result of your program to it.'

>>> assert type(result) is datetime, \
'Variable `result` has an invalid type; expected: `datetime`.'

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

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

# %% Imports
from datetime import datetime

# %% Types
result: datetime

# %% Data
DATA = 'July 21st, 1969'

# %% Result
result = ...


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

# %% 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

# %% 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

# %% Expected
# >>> result
# [datetime.datetime(1969, 7, 21, 0, 0),
#  datetime.datetime(1969, 7, 22, 0, 0),
#  datetime.datetime(1969, 7, 23, 0, 0)]

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

# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0

>>> assert sys.version_info >= (3, 9), \
'Python has an is invalid version; expected: `3.9` or newer.'

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

>>> assert 'result' in globals(), \
'Variable `result` is not defined; assign result of your program to it.'

>>> assert result is not Ellipsis, \
'Variable `result` has an invalid value; assign result of your program to it.'

>>> assert type(result) is list, \
'Variable `result` has an invalid type; expected: `list`.'

>>> assert all(type(x) is datetime for x in result), \
'Variable `result` has elements of an invalid type; all items should be: `datetime`.'

>>> pprint(result, width=30)
[datetime.datetime(1969, 7, 21, 0, 0),
 datetime.datetime(1969, 7, 22, 0, 0),
 datetime.datetime(1969, 7, 23, 0, 0)]
"""

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

# %% Imports
from datetime import date, datetime

# %% Types
result: list[date]

# %% Data
DATA = [
    'July 21st, 1969',
    'July 22nd, 1969',
    'July 23rd, 1969',
]

# %% Result
result = ...