Manipulating strings

foo = "hello, world"

[ e for e in dir(foo) if not e.startswith('_')]

['capitalize',
 'casefold',
 'center',
 'count',
 'encode',
 'endswith',
 'expandtabs',
 'find',
 'format',
 'format_map',
 'index',
 'isalnum',
 'isalpha',
 'isascii',
 'isdecimal',
 'isdigit',
 'isidentifier',
 'islower',
 'isnumeric',
 'isprintable',
 'isspace',
 'istitle',
 'isupper',
 'join',
 'ljust',
 'lower',
 'lstrip',
 'maketrans',
 'partition',
 'replace',
 'rfind',
 'rindex',
 'rjust',
 'rpartition',
 'rsplit',
 'rstrip',
 'split',
 'splitlines',
 'startswith',
 'strip',
 'swapcase',
 'title',
 'translate',
 'upper',
 'zfill']

公式ドキュメント: string methods

大文字小文字変換

print(f"{'abc XYZ'.lower()=}")
print(f"{'abc XYZ'.upper()=}")
print(f"{'abc XYZ'.title()=}")
print(f"{'abc XYZ'.capitalize()=}")
print(f"{'abc XYZ'.swapcase()=}")
print(f"{'abc XYZ'.casefold()=}")

'abc XYZ'.lower()='abc xyz'
'abc XYZ'.upper()='ABC XYZ'
'abc XYZ'.title()='Abc Xyz'
'abc XYZ'.capitalize()='Abc xyz'
'abc XYZ'.swapcase()='ABC xyz'
'abc XYZ'.casefold()='abc xyz'

isXXX判断

print(f"{'42xyz'.isalnum()=}")
print(f"{'google.com'.isalnum()=}")

'42xyz'.isalnum()=True
'google.com'.isalnum()=False

print(f"{'abc'.isalpha()=}")
print(f"{'42'.isalpha()=}")

'abc'.isalpha()=True
'42'.isalpha()=False

import string

print(f"{string.ascii_letters.isascii()=}")
print(f"{'うずまきナルト'.isascii()=}")

string.ascii_letters.isascii()=True
'うずまきナルト'.isascii()=False

print(f"{'1234567890'.isdecimal()=}")
'\u00B2'.isdecimal() # ²

'1234567890'.isdecimal()=True





False

print(f"{'1234567890ABCDEF'.isdigit()=}")
'\u00B2'.isdigit()

'1234567890ABCDEF'.isdigit()=False





True

print(f"{'hello'.isidentifier()=}")
print(f"{'123hao'.isidentifier()=}")

'hello'.isidentifier()=True
'123hao'.isidentifier()=False

print(f"{'普通の文字列の間にアルファベットがあったらislowerが認識する'.islower()=}")
print(f"{'この場合はFalseね'.islower()=}")
print(f"{'同じくISUPPERメソッドも'.isupper()=}")
print(f"{'これはFalseになる'.isupper()=}")
print(f"{'istitleをテストしてみよう'.istitle()=}")
print(f"{'Falseちょうどタイトルの形'.istitle()=}")

'普通の文字列の間にアルファベットがあったらislowerが認識する'.islower()=True
'この場合はFalseね'.islower()=False
'同じくISUPPERメソッドも'.isupper()=True
'これはFalseになる'.isupper()=False
'istitleをテストしてみよう'.istitle()=False
'Falseちょうどタイトルの形'.istitle()=True

#s = '²3455'
s = '\u00B23455'
print(s.isnumeric())
# s = '½'
s = '\u00BD'
print(s.isnumeric())

a = "\u0030" #unicode for 0
print(a.isnumeric())

b = "\u00B2" #unicode for ²
print(b.isnumeric())

c = "10km2"
print(c.isnumeric())

True
True
True
True
False

s.isdigit、isdecimal と s.isnumeric の違い

• isdigit()

  • True: Unicode数字，byte数字（1 Byte），全角数字（2 Bytes）
  • False: 漢字の数字，ローマ数字，小数
  • Error: 無し

• isdecimal()

  • True: Unicode数字，，全角数字（2 Bytes）
  • False: ローマ数字，漢字の数字，小数
  • Error: byte数字（1 Byte）

• isnumeric()

  • True: Unicode 数字，全角数字（2 Bytes），漢字の数字
  • False: 小数，ローマ数字
  • Error: byte数字（1 Byte）

num = "\u00BD"  #unicode
print(f"{num=}")
print(f"{num.isdigit()=}")   # True
print(f"{num.isdecimal()=}") # True
print(f"{num.isnumeric()=}") # True

num = "1" # 全角
print(f"{num=}")
print(f"{num.isdigit()=}")   # True
print(f"{num.isdecimal()=}") # True
print(f"{num.isnumeric()=}") # True

num = b"1" # byte
print(f"{num=}")
print(f"{num.isdigit()=}")   # True
# num.isdecimal() # AttributeError 'bytes' object has no attribute 'isdecimal'
# num.isnumeric() # AttributeError 'bytes' object has no attribute 'isnumeric'

num = "IV" # ローマ数字
print(f"{num=}")
print(f"{num.isdigit()=}")   # False
print(f"{num.isdecimal()=}") # False
print(f"{num.isnumeric()=}") # False

num = "四" # 漢字
print(f"{num=}")
print(f"{num.isdigit()=}")   # False
print(f"{num.isdecimal()=}") # False
print(f"{num.isnumeric()=}") # True

num='½'
num.isdigit()=False
num.isdecimal()=False
num.isnumeric()=True
num='1'
num.isdigit()=True
num.isdecimal()=True
num.isnumeric()=True
num=b'1'
num.isdigit()=True
num='IV'
num.isdigit()=False
num.isdecimal()=False
num.isnumeric()=False
num='四'
num.isdigit()=False
num.isdecimal()=False
num.isnumeric()=True

Unicode Separator

'\u2028'.isprintable()

False

'   '.isspace()

True

分割

print('Hello, world!'.partition('w'))
print('Hello, world!'.partition('world'))
print('Hello, world!'.partition('o'))
print('Hello, world!'.rpartition('o'))
print('Hello, world!'.partition('XYZ'))

('Hello, ', 'w', 'orld!')
('Hello, ', 'world', '!')
('Hell', 'o', ', world!')
('Hello, w', 'o', 'rld!')
('Hello, world!', '', '')

before, sep, after = 'Hello, world!'.partition(' ')
print(f'{before=} {sep=} {after=}')

before='Hello,' sep=' ' after='world!'

print(f"{'月,火,水,木,金,土,日'.split(',')=}")
print(f"{'月,火,水,木,金,土,日'.split(',', 1)=}")

'月,火,水,木,金,土,日'.split(',')=['月', '火', '水', '木', '金', '土', '日']
'月,火,水,木,金,土,日'.split(',', 1)=['月', '火,水,木,金,土,日']

"<hello><><world>".split("<>")

['<hello>', '<world>']

"ab c\n\nde fg\rkl\r\n".splitlines()

['ab c', '', 'de fg', 'kl']

"ab c\n\nde fg\rkl\r\n".splitlines(keepends=True)

['ab c\n', '\n', 'de fg\r', 'kl\r\n']

組み合わせ

print(f"{'_'.join('python')=}")
print(f"{'_'.join(('1', '2' ,'3'))=}")
print(f"{'_'.join(set('python'))=}")
print(f"{'_'.join(['py', 't', 'h', 'on'])=}")
print(f"{'_'.join({'name': 'python', 'age': 29})=}")

'_'.join('python')='p_y_t_h_o_n'
'_'.join(('1', '2' ,'3'))='1_2_3'
'_'.join(set('python'))='o_n_h_p_t_y'
'_'.join(['py', 't', 'h', 'on'])='py_t_h_on'
'_'.join({'name': 'python', 'age': 29})='name_age'

# joinのパラメータは文字列が必要
"_".join((1, 2, 3))

---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-22-2b5a4c7dccb5> in <module>
      1 # joinのパラメータは文字列が必要
----> 2 "_".join((1, 2, 3))


TypeError: sequence item 0: expected str instance, int found

padding

print(f"{'Hello'.ljust(20, '*')=}")
print(f"{'Hello'.rjust(20, '-')=}")
print(f"{'Hello'.center(20, '=')=}")

'Hello'.ljust(20, '*')='Hello***************'
'Hello'.rjust(20, '-')='---------------Hello'
'Hello'.center(20, '=')='=======Hello========'

print(f"{'Hello'.ljust(3, '*')=}")
print(f"{'Hello'.rjust(3, '-')=}")
print(f"{'Hello'.center(3, '=')=}")

'Hello'.ljust(3, '*')='Hello'
'Hello'.rjust(3, '-')='Hello'
'Hello'.center(3, '=')='Hello'

print(f"{'abc'.zfill(5)=}")
print(f"{'-abc'.zfill(5)=}")
print(f"{'+abc'.zfill(5)=}")
print(f"{'42'.zfill(5)=}")
print(f"{'-42'.zfill(5)=}")
print(f"{'+42'.zfill(5)=}")

'abc'.zfill(5)='00abc'
'-abc'.zfill(5)='-0abc'
'+abc'.zfill(5)='+0abc'
'42'.zfill(5)='00042'
'-42'.zfill(5)='-0042'
'+42'.zfill(5)='+0042'

刈り込む

spam = '  Hello, World  '
print(f'{spam.strip()=}')
print(f'{spam.lstrip()=}')
print(f'{spam.rstrip()=}')

spam.strip()='Hello, World'
spam.lstrip()='Hello, World  '
spam.rstrip()='  Hello, World'

spam = 'SpamSpamBaconSpamEggsSpamSpam'
spam.strip('ampS')

'BaconSpamEggs'

探索

print(f"{'abcxyz'.endswith('xyz')=}")
print(f"{'abcxyz'.endswith('xyz', 4)=}")
print(f"{'abcxyz'.endswith('xyz', 0, 5)=}")
print(f"{'abcxyz'.endswith('xyz', 0, 6)=}")

'abcxyz'.endswith('xyz')=True
'abcxyz'.endswith('xyz', 4)=False
'abcxyz'.endswith('xyz', 0, 5)=False
'abcxyz'.endswith('xyz', 0, 6)=True

print(f"{'abcxyz'.startswith(('xyz', 'abc'))=}")

'abcxyz'.startswith(('xyz', 'abc'))=True

print(f"{'xy' in 'abxycd'=}")

'xy' in 'abxycd'=True

print(f"{'abcxyzXY'.find('xy')=}")
print(f"{'abcxyzXY'.find('xy', 4)=}")
print(f"{'abcxyzXY'.find('Xy')=}")

'abcxyzXY'.find('xy')=3
'abcxyzXY'.find('xy', 4)=-1
'abcxyzXY'.find('Xy')=-1

print(f"{'abcxyzabc'.find('abc')=}")
print(f"{'abcxyzabc'.rfind('abc')=}")

'abcxyzabc'.find('abc')=0
'abcxyzabc'.rfind('abc')=6

入れ替え

print(f"{'abcxyzoxy'.replace('xy', 'XY')=}")
print(f"{'abcxyzoxy'.replace('xy', 'XY', 1)=}")
print(f"{'abcxyzoxy'.replace('mn', 'XY', 1)=}")

'abcxyzoxy'.replace('xy', 'XY')='abcXYzoXY'
'abcxyzoxy'.replace('xy', 'XY', 1)='abcXYzoxy'
'abcxyzoxy'.replace('mn', 'XY', 1)='abcxyzoxy'

'01\t012\t0123\t01234'.expandtabs(4) # 2 1 4

'01  012 0123    01234'

'01\t012\t0123\t01234'.expandtabs(8) # 6 5 4

'01      012     0123    01234'

input = string.ascii_letters
output = input[5:] + input[:5]

map_table = str.maketrans(input, output)

'I love You'.translate(map_table)

'N qtAj dtz'

Format

"The sum of 1 + 2 is {0}".format(1 + 2)

'The sum of 1 + 2 is 3'

書式指定文字列の文法

format_spec     ::=  [[fill]align][sign][#][0][width][grouping_option][.precision][type]
fill            ::=  <any character>
align           ::=  "<" | ">" | "=" | "^"
sign            ::=  "+" | "-" | " "
width           ::=  digit+
grouping_option ::=  "_" | ","
precision       ::=  digit+
type            ::=  "b" | "c" | "d" | "e" | "E" | "f" | "F" | "g" | "G" | "n" | "o" | "s" | "x" | "X" | "%"

ip_address = [int(x) for x in "178.124.155.13".split(".")]
"{:02X} {:02X} {:02X} {:02X}".format(*ip_address)

'B2 7C 9B 0D'

ClipBoard

pip install pyperclip

import pyperclip

pyperclip.copy('Hello, World')
pyperclip.paste()

'Hello, World'