文字列

38405 ワード

📌 文字列データ型


👉 文字列=引用符で囲む

"python"
"123"

👉 4つの文字列の作成方法

"python"
'python'
"""python"""
'''python'''

👉 引用符を文字列に含める!


cv変数にIt's my Developgを保存

>>> cv = "It's my velog"

say変数では「It's myvelog」と述べた。保存#ホゾン#

>>> say = '"It is my velog", he says.'

スラッシュの使用()

>>> cv = 'It\'s my velog'
>>> say = "\"It is my velog\", he says."

👉 複数行文字列を変数に挿入


Multiline変数で..。保存#ホゾン#

I love music.
My best thing is dusk till dawn.

nエスケープコードを挿入n

>>> multiple = "I love music.\nMy best thing is dusk till dawn."

連続3つの引用符

>>> multiline = """
I love music.
My best thing is dusk till dawn.
"""

👉 計算文字列


プラス記号

>>> head = "Hi, "
>>> tail = "nice to meet you."
>>> head + tail
'Hi, nice to meet you.'

乗算

>>> a = 'python'
>>> a * 2
'pythonpython'

文字列の長さを求める

>>> a = "Hi, nice to meet you."
>>> len(a)
21

👉 索引とスライド


インデックスとは
ななめに切る

索引

  • ゼロから水が漏れる

  • >>> a = "Hi, nice to meet you."
    >>> a[5]
    'i'
    >>> a[0]
    'H'
  • 逆数(-)

  • >>> a = "Hi, nice to meet you."
    >>> a[-1]
    '.'
    >>> a[-6]
    't'

    索引

  • 終了番号を含める

  • >>> a = "Hi, nice to meet you."
    >>> a[0:2]
    'Hi'
  • さまざまな例

  • >>> a = "Hi, nice to meet you."
    >>> a[0:2]
    'Hi'
    >>> a[:2]
    'Hi'
    >>> a[4:8]
    'nice'
    >>> a[8:]
    ' to meet you.'
    >>> a[:]
    'Hi, nice to meet you.'
    >>> a[4:-13]
    'nice'

    文字列分割

    >>> a = "20210529Rainy"
    >>> date = a[:8]
    >>> weather = a[8:]
    >>> date
    '20210529'
    >>> weather
    'Rainy'

    👉 文字列マッピング


    直接代入数

    >>> "I have %d pens." %3
    'I have 3 pens.'

    文字列の直接代入

    >>> "I have %s pens." %"three"
    'I have three pens.'

    数値を表す変数として入力

    >>> number = 3
    >>> "I have %d pens." %number
    'I have 3 pens.'

    2つ以上の値を入力

    >>> number = 5
    >>> day = "two"
    >>> "I have %d pens that i bought %s days ago" %(number, day)

    全能%s

    >>> "I have %s pens." %5
    'I have 5 pens.'
    >>>"rate is %s" %90.3
    'rate is 90.3'

    「%」を含む

    >>> "Its possibility is %d%%." %90
    'Its possibility is 90%.'

    書式コードと数値の使用

  • 配置とスペース

  • >>> "%10s" %"Hi"
            Hi
    >>> "%-10sTom" %"Hi"
    Hi        Tom
  • 小数点を表す

  • >>> "%0.4f"% 3.141592
    '3.1416'
    >>> "%10.4f"%3.141592
    '    3.1416'

    form関数を使用したマッピング

  • 直接代入数

  • >>> "I have {0} pens".format(3)
    'I have 3 pens
  • 直接文字列を挿入

  • >>> "I have {0} pens".format("three")
    'I have three pens'
  • 数値を表す変数として置換

  • >>> number = 3
    >>> "I have {0} pens".format(number)
  • 複数の値を入力

  • >>> number = 5
    >>> day = "two"
    >>> "I have {0} pens that i bought {1} days ago".format(number, day)
    'I have 5 pens that i bought two days ago
  • 名前を付ける

  • >>> "I have {number} pens that i bought {day} days ago".format(number = 5, day = "two")
    'I have 5 pens that i bought two days ago'
  • インデックスと名前のブレンド

  • >>> "I have {0} pens that i bought {day} days ago".format(3, day="two")
    'I have 3 pens that i bought two days ago'
  • ツールバーの

  • >>> "{0:<10}".format("Hi")
    'Hi        '
    >>> "{0:>10}".format("Hi")
    '        Hi'
    >>>"{0:^10}".format("Hi")
    '    Hi    '
  • 空白を埋める

  • >>> "{0:=^10}".format("Hi")
    '====Hi===='
    >>> "{0:#<10}".format("Hi")
    'Hi########'
  • 小数点

  • >>> a = 3.141592
    >>> "{0:0.4f}".format(a)
    '3.1416'
    >>> "{0:10.4f}".format(a)
    '    3.1416'
  • {または}を表す文字

  • >>> "{{ Hi }}".format()
    '{ Hi }'

    文字列マッピング

  • はい。

  • >>> number = 3
    >>> day = "two"
    >>> f'I have {number} pens that i bought {day} days ago'
  • 式を使用可能にする

  • 'I have 3 pens that i bought two days ago'
    >>> f'I have {number + 1} pens that i bought {day} days ago'
    'I have 4 pens that i bought two days ago'
  • ディックキャンプを使用可能

  • >>> d = {'number':3, 'day':'two'}
    >>> f'I have {d["number"]} pens that i bought {d["day"]} days ago'
    'I have 3 pens that i bought two days ago'
  • ツールバーの

  • >>> f'{"Hi":<10}'
    'Hi        '
    >>> f'{"Hi":>10}'
    '        Hi'
    >>> f'{"Hi":^10}'
    '    Hi    '
  • 空白を埋める

  • >>> f'{"Hi":=^10}'
    '====Hi===='
    >>> f'{"Hi":#<10}'
    'Hi########'
  • 小数点

  • >>> a = 3.141592
    >>> f'{a:0.4f}'
    '3.1416'
    >>> f'{a:10.4f}'
    '    3.1416'
  • {または}を表す文字

  • >>> f'{{ Hi }}'
    '{ Hi }'

    👉 文字列関連関数(8個)


    文字列データ型には、独自の関数があります.文字列変数の後の"."プラスして、関数名を書けばいいです.

    文字数世紀

    >>> a = "bubble"
    >>> a.count('b')
    3

    ヒント位置1(find)

    >>> a = "I have 3 pens that i bought two days ago"
    >>> a.find('s')
    12
    >>> a.find('c')
    -1

    ヒント位置2(index)

    >>> a = "I have 3 pens that i bought two days ago"
    >>> a.index('s')
    12
    >>> a.index('c')
    Traceback (most recent call last):
      File "main.py", line 1, in <module>
        print(a.index('c'))
    ValueError: substring not found

    挿入文字列(join)


    この関数は、文字列だけでなく、リストや凡例も入力できます.
    >>> ",".join('ABCDE')
    A,B,C,D,E

    大文字と小文字の変更

    >>> a = "hi"
    >>> a.upper()
    'HI'
    >>> b = "HI"
    >>> b.lower()
    'hi'

    空白をクリア(lstrip、rstrip、strip)

    >>> a = "   Hi   "
    >>> a.lstrip()
    'Hi   '
    >>> a.rstrip()
    '   Hi'
    >>> a.strip()
    'Hi'

    置換文字列

    >>> a = "My favorite food is pizza"
    >>> a.replace('pizza','chicken')
    'My favorite food is chicken'

    区切り文字列(split)


    カッコに何もない場合は、文字列をスペース(スペース、タブ、エンティティなど)で区切ります.
    >>> a = "My favorite food is pizza"
    >>> a.split()
    ['My' ,'favorite' ,'food' ,'is' ,'pizza']
    >>> b = "a;b;c;d"
    >>> b.split(";")
    ['a', 'b', 'c', 'd']

    文字列の値は変更できません

    >>> a = pithon
    >>> a[1] = 'y'
    Traceback (most recent call last):
      File "main.py", line 2, in <module>
        a[1] = "y"
    TypeError: 'str' object does not support item assignment

    ❗文字列フォーマットコード


    コード摘要%s文字列%c 1文字%d整数%f浮動小数点数%o 8進%x 16進%%テキスト%(文字%自体)

    100 findとindexの違い


    findとindexは、文字列に最初に現れる位置を返します.ただし、検索された文字または文字列が存在しない場合、findは-1、indexはエラーを引き起こします.