How to create custom type from existing value?

By using the dataclass module, we can create custom types from existing values, thus simplifying the code and improving readability: Import the dataclass module. Use the @dataclass decorator to create a custom type and specify the type attributes. Instantiate a custom type using an existing value. Access and manipulate properties in custom types. By creating a custom type from an existing class, we can preserve the methods and properties of the class.

#How to create a custom type from an existing value?

Custom types can help us group data and represent their properties. We can create custom types using existing values, thus simplifying the code and improving readability.

Python

In Python, it is simple to create a custom type using dataclass:

from dataclasses import dataclass

@dataclass
class Coords:
    x: int
    y: int

c = Coords(10, 20)
print(c.x)  # 输出 10
print(c.y)  # 输出 20

Practical case

Suppose we have a Point class with x and y properties:

class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y

We can use This class creates a custom type:

from dataclasses import dataclass

@dataclass
class CustomPoint(Point):
    pass

p = CustomPoint(10, 20)
print(p.x)  # 输出 10
print(p.y)  # 输出 20

By creating a custom type from an existing class, we retain the methods and properties of the class while also getting the benefits of dataclass.

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