python - 如何动态更新Python循环中参数的值？

Question

这里是Python新手:

我正在使用 Pysage 在 Python 中编写市场模拟，并希望使用 mgr.register_actor() 函数生成任意数量的代理(买家或卖家)，如下所示:

for name, maxValuation, endowment, id in xrange(5):
    mgr.register_actor(Buyer(name="buyer001", maxValuation=100, endowment=500),"buyer001")
    update name, maxValuation, endowment, id

运行该函数调用的简洁、Pythonic 方式是什么，以便每次运行循环时，name、maxValuation、endowment 和 id 的值都会更改，例如至 name="buyer002", name="buyer003"...;最大估价=95, 最大估价=90...;捐赠=450，捐赠=400...； “buyer002”、“buyer003”... 等等。

我尝试了不同的 for 循环和列表推导式，但尚未找到一种方法来动态更新函数参数而不遇到类型问题。

提前致谢!

Answer 1

您可以将 names、maxValuations 和 endowments 准备为列表(或迭代器)，然后使用 zip将相应的元素分组在一起:

names=['buyer{i:0>3d}'.format(i=i) for i in range(1,6)]
maxValuations=range(100,75,-5)
endowments=range(500,250,-50)
for name, maxValuation, endowment in zip(names,maxValuations,endowments):
    mgr.register_actor(
        Buyer(name=name, maxValuation=maxValuation, endowment=endowment),name)

---

关于格式字符串，'{i:0>3d}':

当我需要构建格式字符串时，我会引用此“备忘单”:

http://docs.python.org/library/string.html#format-string-syntax
replacement_field ::= "{" field_name ["!" conversion] [":" format_spec] "}"
field_name        ::= (identifier|integer)("."attribute_name|"["element_index"]")* 
attribute_name    ::= identifier
element_index     ::= integer
conversion        ::= "r" | "s"
format_spec       ::= [[fill]align][sign][#][0][width][.precision][type]
fill              ::= <a character other than '}'>
align             ::= "<" | ">" | "=" | "^"
                      "=" forces the padding to be placed after the sign (if any)
                          but before the digits. (for numeric types)
sign              ::= "+" | "-" | " "
                      " " places a leading space for positive numbers
width             ::= integer
precision         ::= integer
type              ::= "b" | "c" | "d" | "e" | "E" | "f" | "F" | "g" | "G" | "n" |
                      "o" | "x" | "X" | "%"

所以，它是这样分解的:

   field_name 
  /
{i:0>3d}
    \\\\
     \\\`-type ("d" means integer)
      \\`-width 
       \`-alignment (">" means right adjust)
        `-fill character