4.6. Idiom All

• Return True if all elements of the iterable are true (or if the iterable is empty).

• Built-in (evaluated)

>>> DATA = [True, False, True]
>>>
>>> all(DATA)
False

4.6.1. Solution

>>> def all(iterable):
...     if not iterable:
...         return False
...     for element in iterable:
...         if not element:
...             return False
...     return True

4.6.2. Use Case - 0x01

>>> all(x for x in range(0,5))
False

4.6.3. Use Case - 0x02

>>> USERS = [
...     {'is_admin': True,  'name': 'Mark Watney'},
...     {'is_admin': True,  'name': 'Melisa Lewis'},
...     {'is_admin': False, 'name': 'Rick Martinez'},
...     {'is_admin': True,  'name': 'Alex Vogel'},
...     {'is_admin': False, 'name': 'Beth Johanssen'},
...     {'is_admin': False, 'name': 'Chris Beck'},
... ]
>>>
>>>
>>> if all(user['is_admin'] for user in USERS):
...     print('Everyone is admin')
... else:
...     print('Not everyone is admin')
Not everyone is admin

4.6.4. Use Case - 0x03

>>> DATA = [
...     ('sepal_length', 'sepal_width', 'petal_length', 'petal_width', 'species'),
...     (5.8, 2.7, 5.1, 1.9, 'virginica'),
...     (5.1, 3.5, 1.4, 0.2, 'setosa'),
...     (5.7, 2.8, 4.1, 1.3, 'versicolor'),
...     (6.3, 2.9, 5.6, 1.8, 'virginica'),
...     (6.4, 3.2, 4.5, 1.5, 'versicolor'),
...     (4.7, 3.2, 1.3, 0.2, 'setosa'),
...     (7.0, 3.2, 4.7, 1.4, 'versicolor'),
... ]
>>>
>>>
>>> all(value > 1.0
...     for *values, species in DATA[1:]
...     for value in values
...     if isinstance(value, float))
False

4.6.5. Performance

Setup:

>>> DATA = [
...     ('sepal_length', 'sepal_width', 'petal_length', 'petal_width', 'species'),
...     (5.8, 2.7, 5.1, 1.9, 'virginica'),
...     (5.1, 3.5, 1.4, 0.2, 'setosa'),
...     (5.7, 2.8, 4.1, 1.3, 'versicolor'),
...     (6.3, 2.9, 5.6, 1.8, 'virginica'),
...     (6.4, 3.2, 4.5, 1.5, 'versicolor'),
...     (4.7, 3.2, 1.3, 0.2, 'setosa'),
...     (7.0, 3.2, 4.7, 1.4, 'versicolor'),
... ]

>>> %%timeit -n 1000 -r 1000  
... result = []
... for row in DATA[1:]:
...     for value in row:
...         if isinstance(value, float):
...             result.append(value >= 1.0)
... result = all(result)
5.24 µs ± 591 ns per loop (mean ± std. dev. of 1000 runs, 1,000 loops each)

>>> %%timeit -n 1000 -r 1000  
... result = True
... for row in DATA[1:]:
...     for value in row:
...         if isinstance(value, float):
...             if not value >= 1.0:
...                 result = False
...                 break
...     if not result:
...         break
1.49 µs ± 596 ns per loop (mean ± std. dev. of 1000 runs, 1,000 loops each)

>>> %%timeit -n 1000 -r 1000  
... result = all(value >= 1.0
...              for row in DATA[1:]
...              for value in row
...              if isinstance(value, float))
1.55 µs ± 436 ns per loop (mean ± std. dev. of 1000 runs, 1,000 loops each)

>>> %%timeit -n 1000 -r 1000  
... result = all(value >= 1.0 for row in DATA[1:] for value in row if isinstance(value, float))
1.51 µs ± 396 ns per loop (mean ± std. dev. of 1000 runs, 1,000 loops each)

>>> %%timeit -n 1000 -r 1000  
... result = all(y >= 1.0 for x in DATA[1:] for y in x if isinstance(y, float))
1.53 µs ± 433 ns per loop (mean ± std. dev. of 1000 runs, 1,000 loops each)

>>> %%timeit -n 1000 -r 1000  
... result = all(x >= 1.0 for X in DATA[1:] for x in X if isinstance(x, float))
1.57 µs ± 437 ns per loop (mean ± std. dev. of 1000 runs, 1,000 loops each)