Tools, FAQ, Tutorials:
'@...' Function Decorators
What are function decorators in Python?
✍: FYIcenter.com
A function decorator is shorthand notation to replace a function with
a new version transformed by a wrapper function.
A function decorator can be specified using the following syntax:
@decorator_wrapper_function def func(): ...
Above Python code is actually equivalent to:
def old_func(): ... func = decorator_wrapper_function(func)
In other words, if a function is decorated, the call expression will call the decorated version of the function.
If multiple decorators are specified, the call expression will call the decorated of the decorated version of the function. So the following Python code:
@a @b @c def f: ...
is the same as:
def f: ... f = a(b(c(f)))
Here is the same example as the previous tutorial in the "@..." decorator format:
>>> def wrapper(dump): ... def newDump(user): ... x = dump(user) ... print("<root>") ... for item in user: ... print("<"+item+">"+str(user[item])+"</"+item+">") ... print("</root>") ... return x ... return newDump ... >>> @wrapper ... def dump(user): ... print(user) ... >>> guest = {"name": "Joe", "age": 25} >>> dump(guest) {'name': 'Joe', 'age': 25} <root> <name>Joe</name> <age>25</age> </root>
⇒ Defining and Using Class for New Data Types
2018-05-08, 2100🔥, 0💬
Popular Posts:
How to extend json.JSONEncoder class? I want to encode other Python data types to JSON. If you encod...
How to convert JSON Objects to PHP Associative Arrays using the json_decode() function? Actually, JS...
How to read RSS validation errors at w3.org? If your RSS feed has errors, the RSS validator at w3.or...
Where can I download the EPUB 2.0 sample book "The Metamorphosis" by Franz Kafka? You can following ...
Where to find tutorials on JSON (JavaScript Object Notation) text string format? I want to know how ...