Python 中的“functoolspartial”是什么？

from functools import partial

partial(func, *args, **kwargs)

def power(base, exponent):    return base ** exponent# create a square function by fixing exponent = 2square = partial(power, exponent=2)# now, square() only needs the baseprint(square(5))  # output: 25print(square(10))  # output: 100

def greet(greeting, name):    return f"{greeting}, {name}!"# fix the greetingsay_hello = partial(greet, greeting="hello")say_goodbye = partial(greet, greeting="goodbye")print(say_hello("alice"))   # output: hello, alice!print(say_goodbye("alice")) # output: goodbye, alice!

def multiply(x, y):    return x * y# fix y = 10multiply_by_10 = partial(multiply, y=10)# use in a mapnumbers = [1, 2, 3, 4]result = map(multiply_by_10, numbers)print(list(result))  # output: [10, 20, 30, 40]

def add(a, b=10):    return a + b# fix b to 20add_with_20 = partial(add, b=20)print(add_with_20(5))  # output: 25

import pandas as pddef filter_rows(df, column, value):    return df[df[column] == value]# fix the column namefilter_by_age = partial(filter_rows, column="age")# example dataframedata = pd.dataframe({"name": ["alice", "bob"], "age": [25, 30]})result = filter_by_age(data, value=25)print(result)

   print(square.func)       # original function (power)   print(square.keywords)   # {'exponent': 2}   print(square.args)       # ()

   print(square(5, exponent=3))  # output: 125 (exponent is overridden)

def apply_discount(price, discount):    return price - (price * discount)# Fix a 10% discountdiscount_10 = partial(apply_discount, discount=0.10)prices = [100, 200, 300]discounted_prices = map(discount_10, prices)print(list(discounted_prices))  # Output: [90.0, 180.0, 270.0]