4. 引号与转义符的使用

目录

• 引号与转义符的使用
  • 概述
  • 引号的使用
  • 转义符
  • 自然字符串

概述

在python中使用引号包裹字符串或doc说明文档。

单引号 ‘

使用单引号指示字符串，所有的空白都会原样保留

双引号 “

在双引号中的字符串与单引号的使用相同

三引号 ‘’’ 或 “”“

利用三引号可以指示一个多行的字符串，在三引号中可以自由的使用单引号或双引号

注意：以上引号在页面中显示不正常，以下面的代码显示为准。

引号的使用

>>> 'Quote me on this'
'Quote me on this'
>>> "Quote me on this"
'Quote me on this'
>>> '''Quote me on this
... the second line
... the third line
... '''
'Quote me on this\nthe second line\nthe third line\n'
>>> """Quote me on this
... the second line
... the third line
... """
'Quote me on this\nthe second line\nthe third line\n'
>>> print('Quote me on this\nthe second line\nthe third line\n')
Quote me on this
the second line
the third line
>>> print('Quote me on this\nthe second line\nthe third line\n')
Quote me on this
the second line
the third line

转义符

使用反斜杠\作为转义符

” # 表示双引号

\ # 表示反斜杠

n # 表示换行符

\ # 行末单独一个反斜杠并不表示转义，而是字符串在下一行继续，并不是开始新的一行。 不使用转义符时，有时会发现错误，python不知道字符串从何处开始，何处结束。

>>> print('this's is a line')
  File "<stdin>", line 1
    print('this's is a line')
                ^
SyntaxError: invalid syntax
>>> print('this\'s is a line')
this's is a line
>>> print("this's is a line.\n"this is the other line"")
  File "<stdin>", line 1
    print("this's is a line.\n"this is the other line"")
                                  ^
SyntaxError: invalid syntax
>>> print("this's is a line.\n\"this is the other line\"")
this's is a line.
"this is the other line"
>>>
>>> print("this's is a line.\
... 'this is not the second line. this is the first line too'"
... )
this's is a line.'this is not the second line. this is the first line too'

自然字符串

如果您不希望一个字符串被转义，通过使用自然字符串可以解决这个问题。

自然字符串通过在字符串前面加上前缀r或R来批指定。

\n 转义后表示换行。

>>> print("this's is a line.\n")
this's is a line.
>>> print(r"this's is a line.\n")
this's is a line.\n
>>> print(R"this's is a line.\n")
this's is a line.\n