隐式变量声明和访问 [英] implicit variable declaration and access

问题描述

是否有任何反射设施在python

我可以用来定义一个存储在另一个变量中的

名称的变量？

就像我有：

x =" myVarName"


如何使用字符串的名称声明一个新变量

存储在x中。我怎样才能在以后隐式访问？

解决方案

Ali Razavi写道：

python中是否有任何反射设施<我可以用来定义一个存储在另一个变量中的
名称的变量吗？
就像我有：
x =" myVarName"

什么我可以用x中存储的字符串名称声明一个新变量。我怎样才能在以后隐式访问？

搞定了！使用像Lisp这样的高阶函数！


code = x +''= 0''

exec（代码）


code =''print''+ x

exec（代码）

Ali Razavi写道：

Ali Razavi写道：

在python中是否有任何反射功能
我可以使用它来定义一个存储在另一个中的名称的变量变量？

搞定了！使用像Lisp这样的高阶函数！


不，你使用像Python这样的高阶函数。 :)

code = x +''= 0''
exec（代码）


一般情况下你应该远离执行原因。我不会详细说明，但搜索这个小组会提供丰富的信息。


如果你想影响全局（你可能不会） t）你可以这样做：$ block $ class =post_quotes> x =''my_var''
globals（）[x] = 7
my_var
7


如果你想在特定对象上设置一个属性（可能是更多的b $ b），你可以这样做：

C类：
....传递

.... c = C（）
setattr（c，x，8）
c.my_var
8

code =''print''+ x
exec（代码）

获得的值分别如下：

print globals（）[x]
7 getattr（c，x）

8

HTH

-

Benji York

Benji York< be *** @ benjiyork.com>写道：


[snap]

code = x +''= 0''
exec（代码）

你应该出于很多原因远离执行官。

代码''可重构' '就是其中之一。

Is there any reflective facility in python
that I can use to define a variable with a
name stored in another variable ?
like I have :
x = "myVarName"

what can I do to declare a new variable with the name of the string
stored in x. And how can I access that implicitly later ?

解决方案

Ali Razavi wrote:

Is there any reflective facility in python
that I can use to define a variable with a
name stored in another variable ?
like I have :
x = "myVarName"

what can I do to declare a new variable with the name of the string
stored in x. And how can I access that implicitly later ?

Got it! use higher order functions like Lisp!

code = x + ''= 0''
exec(code)

code = ''print '' + x
exec(code)

Ali Razavi wrote:

Ali Razavi wrote:

Is there any reflective facility in python
that I can use to define a variable with a
name stored in another variable ?

Got it! use higher order functions like Lisp!
No, you use higher order functions like Python. :)
code = x + ''= 0''
exec(code)
You should generally stay away from exec for lots of reasons. I won''t
elaborate but a search of this group would be informative.

If you want to affect the globals (which you probably don''t) you can
do this:

x = ''my_var''
globals()[x] = 7
my_var 7

If you want to set an attribute on a particular object (which is more
likely), you can do this:
class C: .... pass
.... c = C()
setattr(c, x, 8)
c.my_var 8
code = ''print '' + x
exec(code)

Getting the value would be like this, respectively:
print globals()[x] 7 getattr(c, x)

8

HTH
--
Benji York

Benji York <be***@benjiyork.com> writes:

[snap]

code = x + ''= 0''
exec(code)

You should generally stay away from exec for lots of reasons.

Code ''refactorizability'' is one of them.

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