Core Python Programming (2nd Edition)

False
>>>
>>> 'x' in mixup_list[1]
True
>>> num_list
[[65535L, 2e+030, (76.45-1.3j)], -1.23, 16.0, -49]
>>>
>>> -49 in num_list
True
>>>
>>> 34 in num_list
False
>>>
>>> [65535L, 2e+030, (76.45-1.3j)] in num_list
True
Note how 'x' is not a member of mixup_list. That is because 'x' itself is not actually a member of
mixup_list. Rather, it is a member of mixup_uplist[1], which itself is a list. The membership operator is
applicable in the same manner for tuples.
Concatenation ( + )
The concatenation operator allows us to join multiple lists together. Note in the examples below that
there is a restriction of concatenating like objects. In other words, you can concatenate only objects of
the same type. You cannot concatenate two different types even if both are sequences.
>>> num_list = [43, -1.23, -2, 6.19e5]
>>> str_list = ['jack', 'jumped', 'over', 'candlestick']
>>> mixup_list = [4.0, [1, 'x'], 'beef', -1.9+6j]
>>>
>>> num_list + mixup_list
[43, -1.23, -2, 619000.0, 4.0, [1, 'x'], 'beef', (-1.9+6j)]
>>>
>>> str_list + num_list
['jack', 'jumped', 'over', 'candlestick', 43, -1.23, -2, 619000.0]
As we will discover in Section 6.13, starting in Python 1.5.2, you can use the extend() method in place
of the concatenation operator to append the contents of a list to another. Using extend() is
advantageous over concatenation because it actually appends the elements of the new list to the
original, rather than creating a new list from scratch like + does. extend() is also the method used by the
augmented assignment or in-place concatenation operator (+=), which debuted in Python 2.0.
We would also like to point out that the concatenation operator does not facilitate adding individual
elements to a list. The upcoming example illustrates a case where attempting to add a new item to the
list results in failure.
>>> num_list + 'new item'