Array-based enum in python-CodePudding

I am looking for an enum-based approach to return an array behind each enum item. For example, suppose that I need to specify a range for each type of target such as the following:

from enum import Enum 

class TargetRange(Enum):
    T1 = [0, 100]
    T2 = [30, 60]
    T3 = [50, 150]

Now, I am using the enum like the following:

target_range = TargetRange.T1
value = 140

# ...
# adjust the value

if(value > target_range[1]):
    value = target_range[1]
elif(value < target_range[0]):
    value = target_range[0]
# ...

But, I get the following error:

TypeError: 'TargetRange' object is not subscriptable

How can I resolve it? What is the correct usage of this kind of enum?

I should note that I found this post to return a string (instead of an array). Hence, I am looking for the same idea for returning array instead of a string.

CodePudding user response：

There are three ways to get support for indexing:

use the .value attribute
```
TargetRange.T1.value
```
inherit from list as well as Enum:
```
class TargetRange(list, Enum):
```

add the __getitem__ method:

class TargetRange(Enum):
    def __getitem__(self, index):
        return self._value_[index]
    T1 = [0, 100]
    T2 = [30, 60]
    T3 = [50, 150]

Disclosure: I am the author of the Python stdlib Enum, the enum34 backport, and the Advanced Enumeration (aenum) library.

CodePudding user response：

The difference between Enum and StrEnum is exactly at this point. If you print TargetRange.T1, you will find that the value of the enum item is not returned. Hence, a simple solution to resolve this issue is rewriting your first line of the code as follow:

target_range = TargtetRange.T1.value
#...

It means using .value property of the enum item instead of directly using the enum item.