9.1. Comprehension About¶

Loop leaks out values

>>> result = []
>>>
>>> for x in range(0,5):
...     result.append(x)
>>>
>>> print(result)
[0, 1, 2, 3, 4]
>>>
>>> x
4

>>> result = [x for x in range(0,5)]
>>>
>>> print(result)
[0, 1, 2, 3, 4]
>>>
>>> x  
Traceback (most recent call last):
NameError: name 'x' is not defined

9.1.1. Syntax¶

Abstract Syntax:

>>> 
... result = [<RETURN> for <VARIABLE> in <ITERABLE>]

Short syntax:

>>> [x for x in range(0,5)]
[0, 1, 2, 3, 4]

Long syntax:

>>> list(x for x in range(0,5))
[0, 1, 2, 3, 4]

9.1.2. Good Practices¶

Use shorter variable names
x is common name

9.1.3. Assignments¶

Code 9.1. Solution¶

"""
* Assignment: Comprehension About Create
* Required: yes
* Complexity: easy
* Lines of code: 1 lines
* Time: 3 min

English:
    1. Use list comprehension
    2. Generate `result: list[int]` of numbers from 5 to 20 (without 20)
    3. Run doctests - all must succeed

Polish:
    1. Użyj rozwinięcia listowego
    2. Wygeneruj `result: list[int]` liczb z przedziału 5 do 20 (bez 20)
    3. Uruchom doctesty - wszystkie muszą się powieść

Hints:
    * `range()`

Tests:
    >>> import sys; sys.tracebacklimit = 0

    >>> assert type(result) is list, \
    'Result should be a list'

    >>> assert all(type(x) is int for x in result), \
    'Result should be a list of int'

    >>> result
    [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
"""

# Numbers from 5 to 20 (without 20)
# type: list[int]
result = ...