4.3. Match Or
An OR pattern looks like [*x] | {"elems": [*x]}. It matches if
any of its sub-patterns match. It uses the binding for the leftmost
pattern that matched.
4.3.1. Problem
>>> color = 'red'
>>>
>>> if color == 'r' or color == 'red':
... print('red')
... elif color == 'g' or color == 'green':
... print('green')
... elif color == 'b' or color == 'blue':
... print('blue')
...
red
4.3.2. Solution
>>> color = 'red'
>>>
>>> match color:
... case 'r' | 'red': print('red')
... case 'g' | 'green': print('green')
... case 'b' | 'blue': print('blue')
...
red
4.3.3. Use Case - 1
>>> color = 'r'
>>>
>>> match color:
... case 'r' | 'red': print('#ff0000')
... case 'g' | 'green': print('#00ff00')
... case 'b' | 'blue': print('#0000ff')
...
#ff0000
4.3.4. Use Case - 2
>>> user = 'Watney'
>>>
>>> match user:
... case 'Mark' | 'Watney': print('Hello Mark Watney')
... case 'Melissa' | 'Lewis': print('Hello Melissa Lewis')
... case 'Rick' | 'Martinez': print('Hello Rick Martinez')
... case 'Alex' | 'Vogel': print('Hello Alex Vogel')
... case 'Beth' | 'Johanssen': print('Hello Beth Johanssen')
... case 'Chris' | 'Beck': print('Hello Chris Beck')
...
Hello Mark Watney
4.3.5. Use Case - 3
>>> from http import HTTPStatus
>>> import requests
>>>
>>>
>>> resp = requests.get('https://python3.info')
>>>
>>> match resp.status_code:
... case 200 | 201: print('No error')
... case 300 | 301: print('Redirect')
... case 400 | 401 | 402: print('Client Error')
... case 500 | 501 | 502: print('Server Error')
...
No error
4.3.6. Use Case - 4
SetUp:
>>> SECOND = 1
>>> MINUTE = 60 * SECOND
>>> HOUR = 60 * MINUTE
>>> DAY = 24 * HOUR
>>> WEEK = 7 * DAY
>>> MONTH = 30.4375 * DAY
>>> YEAR = 365.25 * DAY
Definition:
>>> def convert(duration, unit):
... match unit:
... case 's' | 'seconds': return duration / SECOND
... case 'm' | 'minutes': return duration / MINUTE
... case 'h' | 'hours': return duration / HOUR
... case 'd' | 'days': return duration / DAY
... case 'w' | 'weeks': return duration / WEEK
... case 'M' | 'months': return duration / MONTH
... case 'y' | 'years': return duration / YEAR
Usage:
>>> convert(10*HOUR, 'minutes')
600.0
>>>
>>> convert(22*DAY, 'hours')
528.0
4.3.7. Use Case - 5
ares3_landing = datetime(2035, 11, 7)ares3_start = datetime(2035, 6, 29)ares3_duration = timedelta(days=557, seconds=80025)
SetUp:
>>> from dataclasses import dataclass
>>>
>>>
>>> SECOND = 1
>>> MINUTE = 60 * SECOND
>>> HOUR = 60 * MINUTE
>>> DAY = 24 * HOUR
>>> WEEK = 7 * DAY
>>> MONTH = 30.4375 * DAY
>>> YEAR = 365.25 * DAY
>>>
>>> SOL = 24*HOUR + 39*MINUTE + 35*SECOND
Definition:
>>> @dataclass
... class Duration:
... seconds: int
...
... def __format__(self, unit):
... duration = self.seconds
... match unit:
... case 's' | 'seconds': duration /= SECOND
... case 'm' | 'minutes': duration /= MINUTE
... case 'h' | 'hours': duration /= HOUR
... case 'd' | 'days': duration /= DAY
... case 'w' | 'weeks': duration /= WEEK
... case 'M' | 'months': duration /= MONTH
... case 'y' | 'years': duration /= YEAR
... case _: raise TypeError('Invalid unit')
... return f'{duration:.1f} {unit}'
Usage:
>>> ares3 = Duration(543*SOL)
>>>
>>> print(f'Ares3 mission to Mars took {ares3:seconds}')
Ares3 mission to Mars took 48204825.0 seconds
>>>
>>> print(f'Ares3 mission to Mars took {ares3:minutes}')
Ares3 mission to Mars took 803413.8 minutes
>>>
>>> print(f'Ares3 mission to Mars took {ares3:hours}')
Ares3 mission to Mars took 13390.2 hours
>>>
>>> print(f'Ares3 mission to Mars took {ares3:days}')
Ares3 mission to Mars took 557.9 days
>>>
>>> print(f'Ares3 mission to Mars took {ares3:weeks}')
Ares3 mission to Mars took 79.7 weeks
>>>
>>> print(f'Ares3 mission to Mars took {ares3:months}')
Ares3 mission to Mars took 18.3 months
>>>
>>> print(f'Ares3 mission to Mars took {ares3:years}')
Ares3 mission to Mars took 1.5 years