Python 中的输出格式：用相同的变量替换几个 %s答案

【问题标题】：Output formatting in Python: replacing several %s with the same variablePython 中的输出格式：用相同的变量替换几个 %s
【发布时间】：2011-08-08 13:36:50
【问题描述】：

我正在尝试维护/更新/重写/修复一些看起来有点像这样的 Python：

variable = """My name is %s and it has been %s since I was born.
              My parents decided to call me %s because they thought %s was a nice name.
              %s is the same as %s.""" % (name, name, name, name, name, name)

脚本中到处都是这样的小sn-ps，我想知道是否有更简单（更Pythonic？）的方式来编写这段代码。我发现了一个这样的例子，它把同一个变量替换了大约 30 次，感觉很丑。

解决（在我看来）丑陋的唯一方法是把它分成很多小块吗？

variable = """My name is %s and it has been %s since I was born.""" % (name, name)
variable += """My parents decided to call me %s because they thought %s was a nice name.""" % (name, name)
variable += """%s is the same as %s.""" % (name, name)

【问题讨论】：

标签： string-formatting python

【解决方案1】：

改用字典。

var = '%(foo)s %(foo)s %(foo)s' % { 'foo': 'look_at_me_three_times' }

或format 带有明确的编号。

var = '{0} {0} {0}'.format('look_at_meeee')

好吧，或者format 带有命名参数。

var = '{foo} {foo} {foo}'.format(foo = 'python you so crazy')

【讨论】：

您的最后一个选项读起来很漂亮，非常感谢 - 正是我对 Python 的期望！

【解决方案2】：

使用格式化字符串：

>>> variable = """My name is {name} and it has been {name} since..."""
>>> n = "alex"
>>>
>>> variable.format(name=n)
'My name is alex and it has been alex since...'

{} 中的文本可以是描述符或索引值。

另一个花哨的技巧是使用字典结合**运算符来定义多个变量。

>>> values = {"name": "alex", "color": "red"}
>>> """My name is {name} and my favorite color is {color}""".format(**values)
'My name is alex and my favorite color is red'
>>>

【讨论】：

正是我想要的。干净简单。 +1

【解决方案3】：

Python 3.6 引入了一种更简单的字符串格式化方法。您可以在PEP 498获取有关它的详细信息

>>> name = "Sam"
>>> age = 30
>>> f"Hello, {name}. You are {age}."
'Hello, Sam. You are 30.'

它还支持运行时评估

>>>f"{2 * 30}"
'60'

它也支持字典操作

>>> comedian = {'name': 'Tom', 'age': 30}
>>> f"The comedian is {comedian['name']}, aged {comedian['age']}."
 The comedian is Tom, aged 30.

【讨论】：

【解决方案4】：

使用新的string.format：

name = 'Alex'
variable = """My name is {0} and it has been {0} since I was born.
          My parents decided to call me {0} because they thought {0} was a nice name.
          {0} is the same as {0}.""".format(name)

【讨论】：

【解决方案5】：

>>> "%(name)s %(name)s hello!" % dict(name='foo')
'foo foo hello!'

【讨论】：

【解决方案6】：

您可以使用命名参数。 See examples here

【讨论】：

【解决方案7】：

variable = """My name is {0} and it has been {0} since I was born.
              My parents decided to call me {0} because they thought {0} was a nice name.
              {0} is the same as {0}.""".format(name)

【讨论】：

【解决方案8】：

看看Template Strings

【讨论】：

【解决方案9】：

如果您使用的是 Python 3，那么您也可以利用 f-strings

myname = "Test"
sample_string = "Hi my name is {name}".format(name=myname)

到

sample_string = f"Hi my name is {myname}"

【讨论】：