从文本文件中检索变量值的最佳方法? [英] Best way to retrieve variable values from a text file?

问题描述

参考这个问题，我有一个类似的 - 但不是同样的问题..

Referring on this question, I have a similar -but not the same- problem..

在我的路上，我会有一些文本文件，结构如下:

On my way, I'll have some text file, structured like:

var_a: 'home'
var_b: 'car'
var_c: 15.5

我需要 python 读取文件，然后创建一个名为 var_a 的变量，其值为 'home'，依此类推.

And I need that python read the file and then create a variable named var_a with value 'home', and so on.

示例:

#python stuff over here
getVarFromFile(filename) #this is the function that im looking for
print var_b
#output: car, as string
print var_c
#output 15.5, as number.

这可能吗，我的意思是，甚至保留 var 类型?

Is this possible, I mean, even keep the var type?

请注意，我对文本文件结构拥有完全的自由，如果我建议的格式不是最好的，我可以使用我喜欢的格式.

Notice that I have the full freedom to the text file structure, I can use the format I like if the one I proposed isn't the best.

编辑:ConfigParser 可以是一个解决方案，但我不太喜欢它，因为在我的脚本中，我必须使用

EDIT: the ConfigParser can be a solution, but I don't like it so much, because in my script I'll have then to refer to the variables in the file with

config.get("set", "var_name")

但我喜欢的是直接引用变量，正如我在 python 脚本中声明的那样......

But what I'll love is to refer to the variable directly, as I declared it in the python script...

有没有办法将文件导入为python字典?

There is a way to import the file as a python dictionary?

哦，最后一件事，请记住，我不知道文本文件中到底有多少变量.

Oh, last thing, keep in mind that I don't know exactly how many variables would I have in the text file.

编辑 2:我对 stephan 的 JSON 解决方案非常感兴趣，因为这样可以用其他语言(例如 PHP，然后通过 AJAX JavaScript)简单地读取文本文件，但是我在执行该解决方案时失败了:

Edit 2: I'm very interested at stephan's JSON solution, because in that way the text file could be read simply with others languages (PHP, then via AJAX JavaScript, for example), but I fail in something while acting that solution:

#for the example, i dont load the file but create a var with the supposed file content
file_content = "'var_a': 4, 'var_b': 'a string'"
mydict = dict(file_content)
#Error: ValueError: dictionary update sequence element #0 has length 1; 2 is required
file_content_2 = "{'var_a': 4, 'var_b': 'a string'}"
mydict_2 = dict(json.dump(file_content_2, True))
#Error:
#Traceback (most recent call last):
#File "<pyshell#5>", line 1, in <module>
#mydict_2 = dict(json.dump(file_content_2, True))
#File "C:\Python26\lib\json\__init__.py", line 181, in dump
#fp.write(chunk)
#AttributeError: 'bool' object has no attribute 'write'

JSON 格式会导致哪些问题?以及，如何读取文本文件中的 JSON 数组，并将其转换为 Python 字典?

In what kind of issues can I fall with the JSON format? And, how can I read a JSON array in a text file, and transform it in a python dict?

P.S:我不喜欢使用 .py 文件的解决方案；我更喜欢 .txt、.inc、.whatever 不限于一种语言.

P.S: I don't like the solution using .py files; I'll prefer .txt, .inc, .whatever is not restrictive to one language.

推荐答案

使用 JSON<加载您的文件/a> 或 PyYAML 到字典 the_dict(参见 JSON 或 PyYAML 文档对于这一步，两者都可以存储数据类型)并将字典添加到您的全局字典中，例如使用 globals().update(the_dict).

Load your file with JSON or PyYAML into a dictionary the_dict (see doc for JSON or PyYAML for this step, both can store data type) and add the dictionary to your globals dictionary, e.g. using globals().update(the_dict).

如果你想在本地字典中使用它(例如在函数内部)，你可以这样做:

If you want it in a local dictionary instead (e.g. inside a function), you can do it like this:

for (n, v) in the_dict.items():
    exec('%s=%s' % (n, repr(v)))

只要使用 exec 是安全的.如果没有，你可以直接使用字典.

as long as it is safe to use exec. If not, you can use the dictionary directly.

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