Python中的输出格式化：用相同变量替换多个%s

Question

我正在尝试维护/更新/重写/修复一段看起来像这样的Python代码：

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)

在这个脚本的各个地方都有类似的小片段，我在想是否有更简单（更符合Python风格？）的写法。我发现有一个地方的同一个变量被替换了大约30次，感觉实在太难看了。

我觉得唯一解决这种（在我看来）难看的方法就是把它拆分成很多小块吗？

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)

Answer 1

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...'

大括号 {} 里面的内容可以是一个描述符或者一个索引值。

还有一个很酷的技巧是，可以用字典来定义多个变量，并结合 ** 操作符来使用。

>>> 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'
>>>

Answer 2

Python 3.6 引入了一种更简单的字符串格式化方法。你可以在 PEP 498 中找到详细信息。

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

它还支持在运行时进行评估。

>>>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.

Answer 3

用字典来代替吧。

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

或者用format来明确指定数字。

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

当然，也可以用format来指定名字参数。

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