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Decorators in Python

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Decorators in Python

A decorator wraps a function to add behaviour without rewriting its core. @my_decorator above a def is sugar for f = deco(f). Uses: log calls, time a function, check login, cache. Under the hood it is a function that takes a function and returns a new one.

Don’t start with functools.wraps on day one unless they ask. Explain f = deco(f), then one use: timing print. Keep the wrapped function’s job the same.

Decorators in Python — output — HI ASHA. @shout wraps greet and uppercases the result.

Exam tip

f = deco(f) mental model.

Example

# Decorator
def shout(fn):
    def wrap(x):
        return fn(x).upper()
    return wrap

@shout
def greet(name):
    return "hi " + name

print(greet("Asha"))

Decorators in Python — output: HI ASHA. @shout wraps greet and uppercases the result.

Short notes

Def@decorator wraps a function.
Rulef = deco(f).
Uselog / time / auth.

Python · Theory

Decorators in Python

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Theory

85/268

Decorators in Python

Don’t start with functools.wraps on day one unless they ask. Explain f = deco(f), then one use: timing print. Keep the wrapped function’s job the same.

Decorators in Python — output — HI ASHA. @shout wraps greet and uppercases the result.

Exam tip

f = deco(f) mental model.

Example

# Decorator
def shout(fn):
    def wrap(x):
        return fn(x).upper()
    return wrap

@shout
def greet(name):
    return "hi " + name

print(greet("Asha"))

Decorators in Python — output: HI ASHA. @shout wraps greet and uppercases the result.

Short notes

Def@decorator wraps a function.
Rulef = deco(f).
Uselog / time / auth.

Decorators in Python

Example

Short notes

Questions

Decorators in Python

Example

Short notes

Questions