def add1(x): return x+1
add1(3)
4
A function that returns a function:
def logargs(f):
"Print arguments to `f` before calling it"
def _inner(*args, **kwargs):
print(f"Received: {args=}; {kwargs=}")
return f(*args, **kwargs)
return _inner
Using logargs to modify a function:
def _mult2(x): return x*2
mult2 = logargs(_mult2)
mult2(3)
Received: args=(3,); kwargs={}
6
Exactly the same thing but using a decorator as syntax sugar:
@logargs
def mult2(x): return x*2
mult2(3)
Received: args=(3,); kwargs={}
6
A class that takes a function and returns a function:
class logargs:
def __init__(self, prefix='Received: '): self.prefix=prefix
def __call__(self, f):
def _inner(*args, **kwargs):
print(f"{self.prefix}{args=}; {kwargs=}")
return f(*args, **kwargs)
return _inner
Here's how to use it:
def _add1(x): return x+1
o = logargs('Logging: ')
add1 = o(_add1)
add1(3)
Logging: args=(3,); kwargs={}
4
Exactly the same thing but using a decorator as syntax sugar:
@logargs('Logging: ')
def add1(x): return x+1
add1(3)
Logging: args=(3,); kwargs={}
4
from functools import partial
def pow(x,y): return x**y
pow(3,2)
9
squared = partial(pow, y=2)
squared(3)
9