如何格式化可变数量的参数？

Question

我有一个参数列表，我想将其应用于模板格式字符串列表。我的问题是每个模板字符串都可以采用可变数量的参数。我想避免每个字符串需要多少个参数的硬编码列表

counts = [1, 0, 2, 3, 1] # How to get rid of this counts list?
arguments = ["a", "b", "c", "d", "e", "f", "g"] 
templates = [
    "{} one",
    "none",
    "{} two {}",
    "{} {} three {}",
    "one2 {}",
]

start = 0
for i, template in enumerate(templates):
    count = counts[i] # a programmatic way to get the count for current template?
    print(template.format(*arguments[start : start + count]))
    start += count

输出：

一个
无
b 两个 c
d e 三f
一个2克

如何在不知道每种格式需要多少变量的情况下将字符串列表应用于格式模板列表？

Answer 1

您可以使用在模板或参数中不太可能看到的字符连接所有模板，进行字符串插值，然后拆分结果。

templates = [
    "{} one",
    "none",
    "{} two {}",
    "{} {} three {}",
    "one2 {}",
    "and {{literal}} braces {{}}"
]
arguments = ["a", "b", "c", "d", "e", "f", "g"] 

joined_template = chr(1).join(templates)

formatted_string = joined_template.format(*arguments)

formatted_templates = formatted_string.split(chr(1))

formatted_templates 现在是：

['a one',
 'none',
 'b two c',
 'd e three f',
 'one2 g',
 'and {literal} braces {}']

Answer 2

而不是硬编码你的计数，只需count 每个模板中有效大括号的数量。一个简单的方法是这样的：

>>> "{} {} three {}".count("{}")
3
>>> "none".count("{}")
0

所以你的程序看起来像这样：

arguments = ["a", "b", "c", "d", "e", "f", "g"] 
templates = [
    "{{}} one",
    "none",
    "{} two {}",
    "{} {} three {}",
    "one2 {}",
    "and {{literal}} braces {{}}"
]

start = 0
for template in templates:
    count = template.count("{}")
    print(template.format(*arguments[start : start + count]))
    start += count

在 REPL 中：

>>> arguments = ["a", "b", "c", "d", "e", "f", "g"]
>>> templates = [
...     "{} one",
...     "none",
...     "{} two {}",
...     "{} {} three {}",
...     "one2 {}",
...     "and {{literal}} braces {{}}"
... ]
>>>
>>> start = 0
>>> for template in templates:
...     count = template.count("{}")
...     print(template.format(*arguments[start : start + count]))
...     start += count
...
{} one
none
b two c
d e three f
one2 g
and {literal} braces {}