Python3 functools partial 偏函数-昊天SEO

今天我们要讲的偏函数，其实是函数的辅佐，什么意思呢，我们借助Python的help帮助函数，看一下

Python3 functools partial 偏函数-Python 技术分享 Java技术分享 Python 爬虫技术_微信公众号:zeropython—昊天博客

 |  <span class='wp_keywordlink_affiliate'><a href="https://www.168seo.cn/tag/partial" title="View all posts in partial" target="_blank">partial</a></span>(func, *args, **keywords) - new function with <span class='wp_keywordlink_affiliate'><a href="https://www.168seo.cn/tag/partial" title="View all posts in partial" target="_blank">partial</a></span> application
 |  of the given arguments and keywords.

1 2	\| partial(func, args, *keywords) - new function with partial application \| of the given arguments and keywords.

# -*- coding: utf-8 -*-
""" 
@author:songhao 
@file: func.py 
@time: 2018/01/03 
"""
import <span class='wp_keywordlink_affiliate'><a href="https://www.168seo.cn/tag/functools" title="View all posts in functools" target="_blank">functools</a></span>

# print(dir(<span class='wp_keywordlink_affiliate'><a href="https://www.168seo.cn/tag/functools" title="View all posts in functools" target="_blank">functools</a></span>))
from _operator import add

fc = [x for x in dir(functools) if not x.startswith('_')]
print(fc)


# print(help(functools.partial))

def say(name, age):
    return (name, age)


d = functools.partial(say, age=18)

print(d('songhao'))
print(d('songhao',age=28))


# /usr/local/bin/<span class='wp_keywordlink_affiliate'><a href="https://www.168seo.cn/tag/python" title="View all posts in python" target="_blank">python</a></span>3 "/Users/songhao/Desktop/<span class='wp_keywordlink'><a href="http://www.168seo.cn/python" title="python">python</a></span> scrapy/func.py"
# ['MappingProxyType', 'RLock', 'WRAPPER_ASSIGNMENTS', 'WRAPPER_UPDATES', 'WeakKeyDictionary', 'cmp_to_key', 'get_cache_token', 'lru_cache', 'namedtuple', 'partial', 'partialmethod', 'recursive_repr', 'reduce', 'singledispatch', 'total_ordering', 'update_wrapper', 'wraps']
# ('songhao', 18)
# ('songhao', 28)

# -*- coding: utf-8 -*-

"""

@author:songhao

@file: func.py

@time: 2018/01/03

"""

import functools

# print(dir(functools))

from _operator import add

fc = [x for x in dir(functools) if not x.startswith('_')]

print(fc)

# print(help(functools.partial))

def say(name, age):

return (name, age)

d = functools.partial(say, age=18)

print(d('songhao'))

print(d('songhao',age=28))

# /usr/local/bin/python3 "/Users/songhao/Desktop/python scrapy/func.py"

# ['MappingProxyType', 'RLock', 'WRAPPER_ASSIGNMENTS', 'WRAPPER_UPDATES', 'WeakKeyDictionary', 'cmp_to_key', 'get_cache_token', 'lru_cache', 'namedtuple', 'partial', 'partialmethod', 'recursive_repr', 'reduce', 'singledispatch', 'total_ordering', 'update_wrapper', 'wraps']

# ('songhao', 18)

# ('songhao', 28)

functools.partial的作用就是，把一个函数的某些参数给固定住（也就是设置默认值），返回一个新的函数，调用这个新函数会更简单。
冻结参数把多个函数的部分函数进行默认赋值