Python基礎講座 #9 タプル (Tuple)

>>> t1 = (1, 2, 3)
>>> t1
(1, 2, 3)

>>> type(t1)
<class 'tuple'>

>>> t2 = 1, 2, 3
>>> t2
(1, 2, 3)

>>> type(t2)
<class 'tuple'>

>>> l = ['one']
>>> l
['one']

>>> t = ('one')
>>> t
'one'

>>> type(t)
<class 'str'>

>>> t = ('one',)
>>> t
('one',)

>>> type(t)
<class 'tuple'>

>>> t = 1, 2, 3, 4, 5
>>> t[0]
1

>>> t[:3]
(1, 2, 3)

>>> iter(t)
<tuple_iterator object at 0x000002DBC4985640>

>>> for i in t:
...     print(i)
...
1
2
3
4
5

>>> my_list = [1, 2, 3]
>>> my_list[0] = 'one'
>>> my_list
['one', 2, 3]

>>> my_tuple = 1, 2, 3
>>> my_tuple[0] = 'one'
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment
>>> my_tuple
(1, 2, 3)

>>> my_list = [1, 2, 3]
>>> my_list.append(4)
>>> my_list
[1, 2, 3, 4]

>>> my_list.remove(4)
>>> my_list
[1, 2, 3]

>>> my_tuple = 1, 2, 3
>>> my_tuple.append(4)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'tuple' object has no attribute 'append'

>>> help(tuple)
Help on class tuple in module builtins:

class tuple(object)
|  tuple(iterable=(), /)
|
|  Built-in immutable sequence.
|
|  If no argument is given, the constructor returns an empty tuple.
|  If iterable is specified the tuple is initialized from iterable's items.
|
|  If the argument is a tuple, the return value is the same object.
|
|  Built-in subclasses:
|      asyncgen_hooks
|      UnraisableHookArgs
|
|  Methods defined here:
|
|  __add__(self, value, /)
|      Return self+value.
|
|  __contains__(self, key, /)
|      Return key in self.
|
|  __eq__(self, value, /)
|      Return self==value.
|
|  __ge__(self, value, /)
|      Return self>=value.
|
|  __getattribute__(self, name, /)
|      Return getattr(self, name).
|
|  __getitem__(self, key, /)
|      Return self[key].
|
|  __getnewargs__(self, /)
|
|  __gt__(self, value, /)
|      Return self>value.
|
|  __hash__(self, /)
|      Return hash(self).
|
|  __iter__(self, /)
|      Implement iter(self).
|
|  __le__(self, value, /)
|      Return self<=value.
|
|  __len__(self, /)
|      Return len(self).
|
|  __lt__(self, value, /)
|      Return self<value.
|
|  __mul__(self, value, /)
|      Return self*value.
|
|  __ne__(self, value, /)
|      Return self!=value.
|
|  __repr__(self, /)
|      Return repr(self).
|
|  __rmul__(self, value, /)
|      Return value*self.
|
|  count(self, value, /)
|      Return number of occurrences of value.
|
|  index(self, value, start=0, stop=9223372036854775807, /)
|      Return first index of value.
|
|      Raises ValueError if the value is not present.
|
|  ----------------------------------------------------------------------
|  Class methods defined here:
|
|  __class_getitem__(...) from builtins.type
|      See PEP 585
|
|  ----------------------------------------------------------------------
|  Static methods defined here:
|
|  __new__(*args, **kwargs) from builtins.type
|      Create and return a new object.  See help(type) for accurate signature.

>>> t = 1, 2, 2, 2, 3
>>> t.count(2)
3

>>> t.index(3)
4

my_list = ['one', 1, 1.2345, True]
my_tuple = 'one', 1, 1.2345, True

>>> import sys
>>> sys.getsizeof(my_list)
120

>>> sys.getsizeof(my_tuple)
72

# 下のコードはipythonまたはjupyter notebookで実行してください。
In [1]: %timeit my_list = [1, 2, 3, 4, 5]
46.9 ns ± 0.933 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

# 下のコードはipythonまたはjupyter notebookで実行してください。
In [2]: %timeit my_tuple = 1, 2, 3, 4, 5
15.5 ns ± 0.65 ns per loop (mean ± std. dev. of 7 runs, 100000000 loops each)

In [3]: %timeit my_list[0]
37.7 ns ± 1.93 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
In [4]: %timeit my_tuple[0]
36.3 ns ± 1.16 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)