对Python函数设计规范详解

Python函数的设计规范

1、Python函数设计时具备耦合性和聚合性

1）、耦合性：

(1).尽可能通过参数接受输入，以及通过return产生输出以保证函数的独立性；

(2).尽量减少使用全局变量进行函数间通信；

(3).不要在函数中直接修改可变类型的参数；

(4).避免直接改变定义在另外一个模块中的变量；

2）、聚合性：

(1).每个函数都应该有一个单一的、目的统一的目标；

(2).每个函数的功能都应该相对简单；

2、Python函数在脚本中应用示例

例1：将/etc/passwd文件中的每一行都分隔为一个列表

[root@test0528]# vim test1.py

#!/usr/bin/python27

#

importre

filename ='/etc/passwd'

f1 =open(filename,'r')

l1 =f1.readlines()

bash =[]

for i inl1:

bash.append(i)

defgenList(x):

y = 0

x = len(bash)  

while y <= x:

yield bash[y]

y += 1

g1 =genList(bash)

count =0

whilecount < len(bash):

gg=g1.next()

linelist = gg.split(':')

print linelist

count += 1

f1.close()

[root@test0528]# ./test1.py

['root','x', '0', '0', 'root', '/root', '/bin/bash\n']

['bin','x', '1', '1', 'bin', '/bin', '/sbin/nologin\n']

['daemon','x', '2', '2', 'daemon', '/sbin', '/sbin/nologin\n']

......

['nginx','x', '496', '493', 'nginx user', '/var/cache/nginx','/sbin/nologin\n']

['mysql','x', '27', '27', 'MySQL Server', '/var/lib/mysql','/bin/bash\n']

['redis','x', '495', '492', 'Redis Database Server', '/var/lib/redis','/sbin/nologin\n']

例2：将任意文件按用户指定的分隔符把每一行都分隔为一个列表

[root@test0528]# vim test2.py

#!/usr/bin/python27

#

importre

#print"PLease input filename:"

#filename= raw_input()

filename =str(raw_input("PLease input filename: "))

f1 =open(filename,'r')

l1 =f1.readlines()

#print"PLease input separator:"

#separator= raw_input()

separator= str(raw_input("PLease input separator: "))

bash =[]

for i inl1:

bash.append(i)

defgenList(x):

y = 0

x = len(bash)  

while y <= x:

yield bash[y]

y += 1

g1 =genList(bash)

count =0

whilecount < len(bash):

gg=g1.next()

linelist = gg.split(separator)

print linelist

count += 1

f1.close()

[root@test0528]# ./test2.py

PLeaseinput filename: /etc/passwd

PLeaseinput separator: :

['root','x', '0', '0', 'root', '/root', '/bin/bash\n']

['bin','x', '1', '1', 'bin', '/bin', '/sbin/nologin\n']

['daemon','x', '2', '2', 'daemon', '/sbin', '/sbin/nologin\n']

...

['nginx','x', '496', '493', 'nginx user', '/var/cache/nginx','/sbin/nologin\n']

['mysql','x', '27', '27', 'MySQL Server', '/var/lib/mysql','/bin/bash\n']

['redis','x', '495', '492', 'Redis Database Server', '/var/lib/redis','/sbin/nologin\n']

例3：用折叠的方式(reduce)求阶乘

[root@test0528]# vim test3.py

#!/usr/bin/python27

# getn!

num =int(raw_input('please nput a number:'))

num +=1

list =range(1,num)

deffunc(m,n):

return m*n

x =reduce(func,list)

printx

[root@test0528]# ./test3.py

pleasenput a number:4

24

来源：https://blog.csdn.net/Field_Yang/article/details/80587895