#Types of annotations generator
#Types of annotations code

#Types of annotations code

do_api_query ( request ) # Use a 'type: ignore' comment to suppress errors on a given line, # when your code confuses mypy or runs into an outright bug in mypy. reveal_type ( 1 ) # -> Revealed type is 'builtins.int' # Use Union when something could be one of a few types x : list ] = # Use Any if you don't know the type of something or it's too # dynamic to write a type for x : Any = mystery_function () # If you initialize a variable with an empty container or 'None' # you may have to help mypy a bit by providing a type annotation x : list = x : Optional = None # This makes each positional arg and each keyword arg a 'str' def call ( self, * args : str, ** kwargs : str ) -> str : request = make_request ( * args, ** kwargs ) return self. Mypy will print an error # message with the type remove it again before running the code. # An argument can be declared positional-only by giving it a name # starting with two underscores: def quux ( _x : int ) -> None : pass quux ( 3 ) # Fine quux ( _x = 3 ) # Error When you’re puzzled or when things are complicated #įrom typing import Union, Any, Optional, cast # To find out what type mypy infers for an expression anywhere in # your program, wrap it in reveal_type().

#Types of annotations generator

Python 3 supports an annotation syntax for function declarations.įrom typing import Callable, Iterator, Union, Optional # This is how you annotate a function definition def stringify ( num : int ) -> str : return str ( num ) # And here's how you specify multiple arguments def plus ( num1 : int, num2 : int ) -> int : return num1 + num2 # Add default value for an argument after the type annotation def f ( num1 : int, my_float : float = 3.5 ) -> float : return num1 + my_float # This is how you annotate a callable (function) value x : Callable, float ] = f # A generator function that yields ints is secretly just a function that # returns an iterator of ints, so that's how we annotate it def g ( n : int ) -> Iterator : i = 0 while i bool. upper ()) # If a value can never be None due to some invariants, use an assert assert x is not None print ( x. From typing import List, Set, Dict, Tuple, Optional # For simple built-in types, just use the name of the type x : int = 1 x : float = 1.0 x : bool = True x : str = 'test' x : bytes = b 'test' # For collections, the type of the collection item is in brackets # (Python 3.9+) x : list = x : set = # For tuples of fixed size, we specify the types of all the elements x : tuple = ( 3, 'yes', 7.5 ) # Python 3.9+ x : Tuple = ( 3, 'yes', 7.5 ) # For tuples of variable size, we use one type and ellipsis x : tuple = ( 1, 2, 3 ) # Python 3.9+ x : Tuple = ( 1, 2, 3 ) # Use Optional for values that could be None x : Optional = some_function () # Mypy understands a value can't be None in an if-statement if x is not None : print ( x.