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Python 中的 Print

编程语言学习之旅总是从各种 Print 和 Input 语句中开始， Python 也不例外，那你能看出什么问题呢？没有？那我提几个吧……

Python 中的一般 Print 的语法

对单引号('')和双引号("")的显示问题

print 需要用引号来标记输出信息，但如果输出中含有单引号或者双引号时，有时需要转义。

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 >>> print "I don't like Tony's dog."
 I don't like Tony's dog.
 >>> print 'I don"t like Tony"s dog.'
 I don"t like Tony"s dog.

上述例子可以看出，对于两边的引号， Python 会将其默认为标记符，只要句子中的引号和标记符不同，可以不使用转义。

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>>> print "I don't like Tony's dog, But Tony said that I don't care you."
I don't like Tony's dog, But Tony said that I don't care you.
>>> print "I don't like Tony's dog, But Tony said : I don't care you."
I don't like Tony's dog, But Tony said : I don't care you.
>>> print "I don't like Tony's dog, But Tony said: "I don't care you.""
  File "<stdin>", line 1
    print "I don't like Tony's dog, But Tony said: "I don't care you.""
                                                    ^
SyntaxError: invalid syntax
>>> print "I don't like Tony's dog, But Tony said: \"I don't care you.\""
I don't like Tony's dog, But Tony said: "I don't care you."

上述例子看出，如何两边默认的标记符中出现相同的标记符，需要加上转义符号(\)。当然要显示(\)，需要使用(\\)。

转义字符 描述
\(在行尾时) 续行符
\\ 反斜杠符号
\' 单引号
\" 双引号
\a 响铃
\b 退格 (Backspace)
\e 转义
\000 空
\n 换行
\v 纵向制表符
\t 横向制表符
\r 回车
\f 换页
\oyy 八进制数 yy 代表的字符，例如：\o12 代表换行
\xyy 十进制数 yy 代表的字符，例如：\x0a 代表换行
\other 其它的字符以普通格式输出 
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>>> print "Good %s!" % 'luck'
Good luck!
>>> print "Good %r!" % 'luck'
Good 'luck'!
>>> print "Good %r!" % "luck"
Good 'luck'!
>>> print "Hi,%s!" % "Tom's son"
Hi,Tom's son!
>>> print "Hi,%r!" % "Tom's son"
Hi,"Tom's son"!

可以看出， %s 输出为你想要输出的内容，而 %r 输出为原始内容。

input() 和 raw_input() 的区别

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input(...)
    input([prompt]) -> value

    Equivalent to eval(raw_input(prompt)).
(END)
raw_input(...)
    raw_input([prompt]) -> string

    Read a string from standard input.  The trailing newline is stripped.
    If the user hits EOF (Unix: Ctl-D, Windows: Ctl-Z+Return), raise EOFError.
    On Unix, GNU readline is used if enabled.  The prompt string, if given,
    is printed without a trailing newline before reading.
(END)

上述由 pydoc 得到。

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>>> input()
2
2
>>> raw_input()
2
'2'
>>> input(),2
2
(2, 2)
>>> raw_input(),2
2
('2', 2)
>>> [input(),2]
2
[2, 2]
>>> [raw_input(),2]
2
['2', 2]

不知道你发现了什么没有，希望你能够理解。比较不同哦。

相关说明

  • 上述代码在 Python2.7.12 环境下测试
  • 【2017-08-16 19:09:15】更新： python3+ 仅支持 input()