Fungsi sebagai Objek Kelas Pertama

def double(x): return x * 2
fn = double
print(fn(5))
print(type(fn))

def apply(func, val): return func(val)
print(apply(abs, -7))
print(apply(str, 42))

ops = [str.upper, str.lower, str.strip]
for op in ops:
    print(op('  Hello  '))

def make_adder(n):
    def adder(x): return x + n
    return adder
add10 = make_adder(10)
print(add10(5), add10(20))

def counter(start=0):
    count = [start]
    def inc():
        count[0] += 1
        return count[0]
    return inc
c = counter()
print(c(), c(), c())

nums = [3, 1, 4, 1, 5]
print(sorted(nums, key=lambda x: -x))

nums = [1, 2, 3, 4, 5]
print(list(map(lambda x: x**2, nums)))
print(list(filter(lambda x: x%2==0, nums)))

from functools import reduce
print(reduce(lambda a,b: a*b, [1,2,3,4,5]))

print(callable(print))
print(callable(42))
class C:
    def __call__(self): pass
print(callable(C()))

import inspect
def greet(name: str) -> str:
    '''Returns a greeting.'''
    return f'Hi {name}'
print(greet.__name__, greet.__annotations__)
print(inspect.signature(greet))