如何从python类中的实例变量获取所有值的列表

Question

I have a class that looks like this:

class HTTP_HEADERS:
    ACCEPT = "X-Accept"
    DECLINE = "X-Decline"

To get all the variable names out of the class I can do something along the lines of:

members = [
        attr for attr in dir(HTTP_HEADER)
        if not callable(getattr(HTTP_HEADER, attr))
        and not attr.startswith("__")
    ]

This will return a list of variable names, like so:

["ACCEPT", "DECLINE"]

Now what I want to do, is get the values of those variables into a list. For example the output should be:

["X-Accept", "X-Decline"]

How can I do this successfully?

Answer 1

If you have this:

class HTTP_HEADER:
    ACCEPT = "X-Accept"
    DECLINE = "X-Decline"

names = ["ACCEPT", "DECLINE"]

Getting the values is simply a matter of

values = [getattr(HTTP_HEADER, name) for name in names]

I think a dictionary is more appropriate though, and it can be done with minimal change to your original code:

members = {
        k: v for k, v in vars(HTTP_HEADER).items()
        if not callable(v)
        and not k.startswith("__")
    }

which gives

{'ACCEPT': 'X-Accept', 'DECLINE': 'X-Decline'}

Answer 2

You should define this as an Enum .

class HTTP_HEADERS(enum.Enum):
    ACCEPT = "X-Accept"
    DECLINE = "X-Decline"

Now you can simply do:

[x.value for x in HTTP_HEADERS]

Answer 3

Use getattr again to access class variable

[getattr(HTTP_HEADERS,m) for m in members]

Output

['X-Accept', 'X-Decline']