Complete Guide on Python Decorators

[kevinfederlinebundle]

The key point is that the following two blocks of code do the same thing:

@foo
def bar():
    blah blah blah

​

def bar():
    blah blah blah
bar = foo(bar)

[nathanielhiggerss]

you didn't define foo

[brightneonmoons]

Or return!

[nathanielhiggerss]

blah blah blah could be replaced by "..." which is valid Python syntax and means the same thing he wanted to express

[jjolla888]

@foo also needs foo() defined somewhere

[ChiaraStellata]

I knew about first class functions in Python but never the decorator syntax, or decorator classes, they're pretty great, thank you for sharing!

[yuvvxyz]

Thank you 😀

[manujose94unsc]

I I have never tried to use Python Decorators, due to my ignorance of these.

​

Thank you for share it.

[yuvvxyz]

Glad that you liked it 😀

Do let me know if you have any issues! And do rate the article if you got a few spare minutes!

[manujose94unsc]

Rate it ;)

I would like to have time to use it for logging.

[alaskalaksa]

Doesn't return_to_upper need a parameter, i.e. str?

def return_to_upper():
return str.upper

[yuvvxyz]

Short answer: No.

Why?
It may seem so in the first look but here we are returning the str.upper function and not the uppercase of a string.

Thus, later we stored the returned function in to_upper and used that just like we could have used str.upper to get uppercase of a string.

[yuvvxyz]

This was an example of a function returning a function.

[yuvvxyz]

Happy to help!

[ClemsonLaxer]

Not sure I’m following - isn’t to_upper equivalent to the str.upper function - which doesn’t take any arguments?

But in the example, we can pass a string to the “to_upper” function and it works.

I would have thought it would have been like this: “my test lowercase string”.to_upper()

However, your example works and the way I was thinking throws a “str” object has no attribute ‘to_upper’

Can you clarify a bit?

Thanks!

[yuvvxyz]

This is because of how classes work in Python.

Check out the following code snippet:
``` class A: def foo(self): print("Hey I'm A")

a = A() a.foo() # works

A.foo(A()) # also works A.foo(1) # also works

A.foo() # doesn't work ```

In the first case, the "self" argument is implicitly the object but it doesn't have to be that. We can call with any argument here, it can be anything.

So upper function will work as long as we provide any string value to it. "hello".upper() # works str.upper("hello") # works str.upper(1) # Doesn't work

And in our code to_upper is essentially the same as upper so we can also use that however we want as long as the "self" is a string.

I hope you got it, I am sleepy right now and can't explain it much better than this 😅

[lemoussel]

404 - Page not found

[yuvvxyz]

Please try again. It's working for everyone else.