List & Tuple : an ordered collection of objects

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python テキストリンク
List & Tuple : an ordered collection of objects
realpython

リスト機能


1. Lists Are Ordered

>>> [1, 2, 3, 4] == [4, 1, 3, 2]
False

2. Lists Can Contain Arbitrary Objects

[21.42, 'foobar', 3, 4, 'bark', False, 3.14159]

>>> a = [int, len, foo, math]
>>> a
[<class 'int'>, <built-in function len>, <function foo at 0x02CA2618>,
<module 'math' (built-in)>]

3. List Elements Can Be Accessed by Index


: to accessing individual characters in a string
  • len() 
    • >>> a = ['foo', 'bar', 'baz', 'qux', 'quux', 'corge']

>>> print(a[2:], a[2:len(a)])
['baz', 'qux', 'quux', 'corge'] ['baz', 'qux', 'quux', 'corge']
  • stride 
    • >>> a[0:6:2]
['foo', 'baz', 'quux']
>>> a[1:6:2]
['bar', 'qux', 'corge']
>>> a[6:0:-2]
['corge', 'qux', 'bar']
  • reverse 
    • >>> a[::-1]
['corge', 'quux', 'qux', 'baz', 'bar', 'foo']

>>> 'If Comrade Napoleon says it, it must be right.'[::-1]
'.thgir eb tsum ti ,ti syas noelopaN edarmoC fI'
  • how the [:] syntax works with a string
    : If s is a string, s[:] returns a reference to the same object: 
    • >>> s = 'foobar'
>>> s[:]
'foobar'
>>> s[:] is s
True
    : Conversely, if a is a list, a[:] returns a new object that is a copy of a:
    >>> a[:]
['foo', 'bar', 'baz', 'qux', 'quux', 'corge']
>>> a[:] is a
False
  • built-in functions 
    • ## in/not in
>>> a
['foo', 'bar', 'baz', 'qux', 'quux', 'corge']

>>> 'qux' in a
True
>>> 'thud' not in a
True

## concatenation(+) ,replication(*)
>>> a + ['grault', 'garply']
['foo', 'bar', 'baz', 'qux', 'quux', 'corge', 'grault', 'garply']
>>> a * 2
['foo', 'bar', 'baz', 'qux', 'quux', 'corge', 'foo', 'bar', 'baz',
'qux', 'quux', 'corge']

## The len(), min(), and max() functions:
>>> len(a)
6
>>> min(a)
'bar'
>>> max(a)
'qux'

    4. Lists Can Be Nested


    >>> x = ['a', ['bb', ['ccc', 'ddd'], 'ee', 'ff'], 'g', ['hh', 'ii'], 'j']

>>> x[1]
['bb', ['ccc', 'ddd'], 'ee', 'ff']

>>> x[1][1]
['ccc', 'ddd']

>>> print(x[3][0], x[3][1])
hh ii

>>> x[1][1:3]
[['ccc', 'ddd'], 'ee']
>>> x[3][::-1]
['ii', 'hh']

    5. Lists Are Mutable

    >>> a = ['foo', 'bar', 'baz', 'qux', 'quux', 'corge']

>>> a[2] = 10
>>> a[-1] = 20
>>> a
['foo', 'bar', 10, 'qux', 'quux', 20]

>>> del a[3]
>>> a
['foo', 'bar', 'baz', 'quux', 'corge']
  • insert multiple elements using a slice 
    • >>> a = [1, 2, 3]
>>> a[1:2] = [2.1, 2.2, 2.3]
>>> a
[1, 2.1, 2.2, 2.3, 3]
  • insert multiple elements using a list 
    • >>> a = [1, 2, 3]
>>> a[1] = [2.1, 2.2, 2.3]
>>> a
[1, [2.1, 2.2, 2.3], 3]
  • insert elements into a list without removing anything 
    • >>> a = [1, 2, 7, 8]
>>> a[2:2] = [3, 4, 5, 6]
>>> a
[1, 2, 3, 4, 5, 6, 7, 8]
  • delete multiple elements 
    • >>> a = ['foo', 'bar', 'baz', 'qux', 'quux', 'corge']
>>> a[1:5] = []
>>> a
['foo', 'corge']

>>> a = ['foo', 'bar', 'baz', 'qux', 'quux', 'corge']
>>> del a[1:5]
>>> a
['foo', 'corge']
  • Prepending(プレフィックス)またはAppending(添付ファイル)Items to a list 
    • >>> a += ['grault', 'garply']
>>> a
['foo', 'bar', 'baz', 'qux', 'quux', 'corge', 'grault', 'garply']

>>> a = [10, 20] + a
>>> a
[10, 20, 'foo', 'bar', 'baz', 'qux', 'quux', 'corge']

>>> a += 'corge'
>>> a
['foo', 'bar', 'baz', 'qux', 'quux', 'c', 'o', 'r', 'g', 'e']
  • a.append(obj)
    :新規リスト
    • を作成せずに変更
    a = ['a', 'b']
>>> a.append(123)
>>> a
['a', 'b', 123]

>>> x = a.append(123)
>>> print(x)
None
>>> a
['a', 'b', 123]
  • concatenation(+) vs Prepending(+=) vs .append vs .extend 
    • >>> a = ['a', 'b']
>>> a + [1, 2, 3]
['a', 'b', 1, 2, 3]

>>> a.append([1, 2, 3])
>>> a
['a', 'b', [1, 2, 3]]

# Thus, with .append(), you can append a string as a single entity:
>>> a.append('foo')
>>> a
['a', 'b', 'foo']

>>> a.extend([1, 2, 3])
>>> a
['a', 'b', 1, 2, 3]

>>> a += [1, 2, 3]
>>> a
['a', 'b', 1, 2, 3]
  • .insert(index, obj) 
    • >>> a.insert(3, 3.14159)
>>> a[3]
3.14159
>>> a
['foo', 'bar', 'baz', 3.14159, 'qux', 'quux', 'corge']
  • .remove(obj) 
    • >>> a = ['foo', 'bar', 'baz', 'qux', 'quux', 'corge']
>>> a.remove('baz')
>>> a
['foo', 'bar', 'qux', 'quux', 'corge']
  • .pip(defalt=-1) 
    • >>> a = ['foo', 'bar', 'baz', 'qux', 'quux', 'corge']
>>> a.pop()
'corge'
>>> a
['foo', 'bar', 'baz', 'qux', 'quux']

>>> a.pop()
'quux'
>>> a
['foo', 'bar', 'baz', 'qux']

    6. Lists Are Dynamic


    : When items are added to a list, it grows as needed
    >>> a[2:2] = [1, 2, 3]
>>> a += [3.14159]
>>> a
['foo', 'bar', 1, 2, 3, 'baz', 'qux', 'quux', 'corge', 3.14159]

>>> a[2:3] = []
>>> del a[0]
>>> a
['bar', 'qux', 'quux', 'corge']

    Tuple


    :tupleは次の2種類を除き、Listと同じです.
  • ()
    • を使用
  • Tuples are immutable.
    • なぜリストではなくTupleを使うのですか?
  • チュートリアルは、リスト実行プログラムよりも高速です.
  • のデータを変更したくない場合.セット内の値がプログラムの実行中に一致していることを確認し、予期せぬ変更を防ぐことができます.
  • の別のPythonデータ型dictionaryでは、KEYには不変の値が必要です.この目的のためにパレットを使用できますが、リストは使用できません.

    • 調音機能


    :tupleは[]の代わりにカッコ(カッコ)を使用しますが、stringやlistと同様にインデックスやシートも使用できます.
    >>> t = ('foo', 'bar', 'baz', 'qux', 'quux', 'corge')

>>> t[0]
'foo'
>>> t[-1]
'corge'
>>> t[1::2]
('bar', 'qux', 'corge')

>>> t[::-1]
('corge', 'quux', 'qux', 'baz', 'bar', 'foo')
  • 1個の項目のみを使用する場合は、カンマ(,)
    • を使用します.
    >>> t = (2)
>>> type(t)
<class 'int'>

>>> t = (2,)
>>> type(t)
<class 'tuple'>
>>> t[0]
2
>>> t[-1]
2

    Tuple Assignment, Packing, and Unpacking

  • Assignment 
    • >>> t = ('foo', 'bar', 'baz', 'qux')
  • Packing
    the items in the tuple have been “packed” into the object:
    • >>> t
('foo', 'bar', 'baz', 'qux')
>>> t[0]
'foo'
>>> t[-1]
'qux'
  • Unpakcing
    If that “packed” object is subsequently assigned to a new tuple, the individual items are “unpacked” into the objects in the tuple:
    • >>> (s1, s2, s3, s4) = t
>>> s1
'foo'
>>> s2
'bar'
>>> s3
'baz'
>>> s4
'qux'
  • swap

    • まとめとまとめ


    インベントリ

  • インデックスおよびメソッドを使用するため、値を動的に変更およびソートすることが容易である.
  • デフォルトでは[]四角カッコ
    • を使用します.
  • ダイナミック.
    • 保存と削除が容易
  • tupleとの違い:リストの使用方法は任意に値を変更できますが、tupleは変更されていません.
  • ディレクトリとの違いは、リストはインデックスによって値にアクセスできますが、ディレクトリはインデックスを使用できません.(キーアクセス値)
  • のPythonリストは計算方法を有し,非単純な資料型の資料構造形式を有する.
  • アレイの機能:複数の値を格納
  • すべてのデータ型
  • 多次元リスト(リストスキーマリスト)다차원 리스트는 게입개발, 대규모 머신러닝 알고리즘에서 사용된다
  • は、リスト
    • を特定の変数に保存することができる.
    配備[Bundler]Webpack Netlify|Npx|Degit
    JNI GetFieldID属性タイプの判断