本文主要是介绍Python3 functools partial 偏函数，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
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
| <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)
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | # -*- 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
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