Class Members and Methods

suggest change
class A:
    x = None  # type: float
    def __init__(self, x: float) -> None:
        """
        self should not be annotated
        init should be annotated to return None
        """
        self.x = x
    
    @classmethod
    def from_int(cls, x: int) -> 'A': 
        """
        cls should not be annotated
        Use forward reference to refer to current class with string literal 'A'
        """
        return cls(float(x))

Forward reference of the current class is needed since annotations are evaluated when the function is defined. Forward references can also be used when referring to a class that would cause a circular import if imported.

Feedback about page:

Feedback:
Optional: your email if you want me to get back to you:


Type Hints:
* Class Members and Methods

Table Of Contents
2 Filter
3 List
7 Loops
22 Reduce
27 Classes
31 Set
42 Tuple
45 Enum
62 Sockets
67 Type Hints
89 urllib
92 Idioms
104 Stack
105 Profiling
109 Logging
111 os module
118 Mixins
120 ArcPy
126 Arrays
132 2to3 tool
135 Unicode
138 Neo4j
140 Curses
141 Templates
145 heapq
146 tkinter
154 Audio
155 pyglet
157 ijson
160 Flask
161 Groupby
163 pygame
165 hashlib
166 Gzip
167 ctypes
185 pyaudio
186 shelve