7.16. Regex Quantifier Shorthand

7.16.1. SetUp

>>> import re

7.16.2. 1 to Infinity

+ - minimum 1 repetitions, no maximum, prefer longer (alias to {1,})
+? - minimum 1 repetitions, no maximum, prefer shorter (alias to {1,}?)

Greedy:

>>> string = 'Hello 1234'
>>>
>>>
>>> re.findall(r'\d{1,}', string)
['1234']
>>>
>>> re.findall(r'\d+', string)
['1234']

Lazy:

>>> string = 'Hello 1234'
>>>
>>>
>>> re.findall(r'\d{1,}?', string)
['1', '2', '3', '4']
>>>
>>> re.findall(r'\d+?', string)
['1', '2', '3', '4']

7.16.3. 0 to Infinity

* - minimum 0 repetitions, no maximum, prefer longer (alias to {0,})
*? - minimum 0 repetitions, no maximum, prefer shorter (alias to {0,}?)

Greedy:

>>> string = 'Hello 1234'
>>>
>>>
>>> re.findall(r'\d{0,}', string)
['', '', '', '', '', '', '1234', '']
>>>
>>> re.findall(r'\d*', string)
['', '', '', '', '', '', '1234', '']

Lazy:

>>> string = 'Hello 1234'
>>>
>>>
>>> re.findall(r'\d{0,}?', string)
['', '', '', '', '', '', '', '1', '', '2', '', '3', '', '4', '']
>>>
>>> re.findall(r'\d*?', string)
['', '', '', '', '', '', '', '1', '', '2', '', '3', '', '4', '']

7.16.4. 0 or 1 (Optional)

? - minimum 0 repetitions, maximum 1 repetitions, prefer longer (alias to {0,1})
?? - minimum 0 repetitions, maximum 1 repetition, prefer shorter (alias to {0,1}?)

Greedy:

>>> string = 'Hello 1234'
>>>
>>>
>>> re.findall(r'\d{0,1}', string)
['', '', '', '', '', '', '1', '2', '3', '4', '']
>>>
>>> re.findall(r'\d?', string)
['', '', '', '', '', '', '1', '2', '3', '4', '']

Lazy:

>>> string = 'Hello 1234'
>>>
>>>
>>> re.findall(r'\d{0,1}?', string)
['', '', '', '', '', '', '', '1', '', '2', '', '3', '', '4', '']
>>>
>>> re.findall(r'\d??', string)
['', '', '', '', '', '', '', '1', '', '2', '', '3', '', '4', '']