如何串联对象以在Python中创建或调用变量？ -编辑 [英] How to concatenate objects to create or call a variable in Python? - EDITED

问题描述

在我习惯的其他一些编程语言中，有一种方法可以动态创建和调用变量。

In some other programming languages I am used to, there was a way to dynamically create and call variables. How to do this in Python?

例如，假设变量名为test1； test2等，直到test9，我想这样称呼他们：

For example let's suppose variables called test1; test2 etc. up to test9, and I want to call them like this:

for n in range(1,10):
    print concatenate('test', n)

当然，函数concatenate是我在找一个。

Of course, the function concatenate is the one I am looking for.

以这种方式组合字符串，整数和正则表达式的命令是什么？

What is the command to combine strings, integers and regular expressions in this way?

我的示例是一个不好的示例，使某些答案提示字典或其他类似方法。我可能对它们不太自信，或者不能在所有情况下都使用它们。这是另一个示例：

My example was a bad one, that made some of the answers suggest dictionary, or some other similar methods. It's either I am not too confident with them, or I can't use them in all cases. Here's another example:

假设我们有一个包含4行4列的表，并且该表中包含一些数字。我想做一些特殊的数学运算，将行号，列号和变量作为输入，并为另一个数学运算输出另一个行-列对。

Let's suppose we have a table of 4 rows and 4 columns, and the table has some numbers in it. I want to do some special mathematical operations, which has the row number, column number and the variable as inputs, and it outputs another row-column pair for another mathematical operation.

逻辑建议我，最简单的方法是拥有16个变量，并在其名称中包含行号和列号。而且，如果我可以使用变量名称进行操作，并返回结果并将其称为另一个varialbe，那么问题就很容易了。

Logic suggests me that te easiest way to do this would be to have 16 variables, having row and column number in their names. And if I could do operations with the names of the variables, and also return the result and call it as another varialbe, the problem would be easy.

这种情况呢？ ？

推荐答案

您可以使用 globals ，它返回有关全局范围的字典：

You could use globals, which returns a dictionary of what is in the global scope:

>>> test1 = 'a'
>>> test2 = 'b'
>>> test3 = 'c'
>>> globals()
{'test1': 'a', 'test3': 'c', 'test2': 'b', '__builtins__': <module '__builtin__' (built-in)>, '__package__': None, '__name__': '__main__', '__doc__': None}
>>> for n in range(1, 4):
...     print globals()["test" + str(n)]  # Dynamically access variables
...
a
b
c
>>> for n in range(1, 4):
...     globals()["dynamic" + str(n)] = n  # Dynamically create variables
...
>>> dynamic1
1
>>> dynamic2
2
>>> dynamic3
3
>>>

但是，我不建议您实际执行此操作。这是丑陋的，骇人听闻的，实际上只是一种不好的做法。

However, I do not recommend that you actually do this. It is ugly, hackish, and really just a bad practice.

最好删除数字变量，而使用< a href = https://docs.python.org/2/library/stdtypes.html#typesseq rel = nofollow>列表，该列表会自动按索引编号其项目：

It would be much better to do away with your numbered variables and instead use a list, which will automatically number its items by index:

>>> lst = ['a', 'b', 'c']
>>> lst[0]  # Equivalent to test1
'a'
>>> lst[1]  # Equivalent to test2
'b'
>>> lst[2]  # Equivalent to test3
'c'
>>> for i in lst:  # You can iterate directly over the list too
...     print i
...
a
b
c
>>> lst.append('d') # "Creating" a new object is easy and clean
>>> lst
['a', 'b', 'c', 'd']
>>>

基本上，而不是 test1 ， test2 ， test3 ...您现在拥有 lst [0] ， lst [1] ， lst [2] ...

Basically, instead of test1, test2, test3...you now have lst[0], lst[1], lst[2]...

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