1 math和cmath模块分别包含了计算实数和复数的数学函数
2 任何Python程序都可以作为模块导入。windows为例 C:\python 目录下的hello.py文件
import sys
sys.path.append('C:/python')
import hello
在导入模块时代码将被执行，第二次导入则不再执行——导入模块主要用于定义
__name__ 在主程序中，值为'__main__',在导入的模块中，这个值就是模块名，例如hello2
#hello.py
def hello():
print 'Hello,world!'
def test():
hello()
if __name__ == '__main__' : test()
>>> import sys
>>> sys.path.append('C:/Python25/')
>>> import hello
>>> hello.hello()
Hello,world!
>>> hello.test()
Hello,world!
3 将模块放在合适的位置中，实现sys.path本身就含有正确的目录，如下： 或者修改环境变量PYTHONPATH
>>> import sys,pprint
>>> pprint.pprint(sys.path)
['F:/Python',
'C:\\Python25\\Lib\\idlelib',
'C:\\Windows\\system32\\python25.zip',
'C:\\Python25\\DLLs',
'C:\\Python25\\lib',
'C:\\Python25\\lib\\plat-win',
'C:\\Python25\\lib\\lib-tk',
'C:\\Python25',
'C:\\Python25\\lib\\site-packages',
'C:/Python25/']
其实，site-packages是专门用来放置用户自定义的模块的。
4 import 模块名
dir(模块名) 查看模块中的内容，他会将对象以及模块的所有函数、类、变量等的所有特性列出来
__all__ 定义模块的公有接口，没有的话，import *语句默认将会输出模块中所有不以下划线开头的全局名称
5
win (unix和mac os x） mac os
os.sep \\ / :
os.pathsep ; : ::
os.linesep \r\n \n换行符 \r单个回车符
6 为文件编写行号
#numberline.py
import fileinput
for line in fileinput.input(inplace = True):
line = line.rstrip()
num = fileinput.lineno()
print '%-40s #%2i' %(line,num)
多次运行，每行将添加多个行号
7 集合
>>> set(range(10))
set([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> a = set([1,2,3])
>>> b = set([2,3,4])
>>> a.union(b)
set([1, 2, 3, 4])
>>> a
set([1, 2, 3])
>>> a|b
set([1, 2, 3, 4])
>>> a
set([1, 2, 3])
>>> b
set([2, 3, 4])
>>> c = a&b
>>> c
set([2, 3])
>>> a
set([1, 2, 3])
>>> b
set([2, 3, 4])
>>> c.issubset(b)
True
>>> c <= a
True
>>> c<=b
True
>>> b<=a
False
>>> a.issuperset(c)
True
>>> a.issuperset(a)
True
示例 打印并集与reduce函数结合
>>> myset = []
>>> for i in range(10):
myset.append(set(range(i,i+5)))
>>> myset
[set([0, 1, 2, 3, 4]), set([1, 2, 3, 4, 5]), set([2, 3, 4, 5, 6]), set([3, 4, 5, 6, 7]), set([8, 4, 5, 6, 7]), set([8, 9, 5, 6, 7]), set([8, 9, 10, 6, 7]), set([8, 9, 10, 11, 7]), set([8, 9, 10, 11, 12]), set([9, 10, 11, 12, 13])]
>>> reduce(set.union,myset)
set([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13])
关于frozenset函数
>>> a = set()
>>> b = set()
>>> a.add(b)
Traceback (most recent call last):
File "<pyshell#85>", line 1, in <module>
a.add(b)
TypeError: set objects are unhashable
>>> a.add(frozenset(b))
>>> a
set([frozenset([])])
>>> b
set([])
>>> a.add(b)
Traceback (most recent call last):
File "<pyshell#89>", line 1, in <module>
a.add(b)
TypeError: set objects are unhashable
==================================================================
1 random模块使用示例P187
#pocker.py
values = range(1,11) + 'Jack Queen King'.split()suits = 'diamonds clubs hearts spades'.split()
deck = ['%s of %s' %(v,s) for v in values for s in suits]
from pprint import pprint
#输出原始的前12张
pprint(deck[:12])
from random import shuffle
shuffle(deck)
#输出打乱后的前12张
pprint(deck[:12])
#每次回车发一张牌，直到所有牌都发完
while deck:
raw_input(deck.pop())
2 P189 简单的数据库应用程序
#简单的数据库应用程序
#database.py
import sys, shelve
def store_person(db):
"""
Query user for data and store it in the shelf object
"""
pid = raw_input('Enter unique ID number: ')
person = {}
person['name'] = raw_input('Enter name: ')
person['age'] = raw_input('Enter age: ')
person['phone'] = raw_input('Enter phone number: ')
db[pid] = person
def lookup(db):
"""
Query user for ID and desired field, and fetch the corresponding data
from the shelf object
"""
pid = raw_input('Enter ID number: ')
field = raw_input('What would you like to know? (name,age,phone) ')
field = field.strip().lower()
print field.capitalize() + ':',\
db[pid][field]
def print_help():
print 'The available commands are:'
print 'store : Stores information about a person'
print 'lookup : Looks up a person from ID number'
print 'quit : Save changes and exit'
print '? : Prints this message'
def enter_command():
cmd = raw_input('Enter command(? for help)')
cmd = cmd.strip().lower()
return cmd
def main():
database = shelve.open('F:\\database.dat')
try:
while True:
cmd = enter_command()
if cmd == 'store':
store_person(database)
elif cmd == 'lookup':
lookup(database)
elif cmd == '?':
print_help()
elif cmd == 'quit':
return
finally:
database.close()
if __name__ == '__main__': main()
运行示例
>>>
Enter command(? for help)?
The available commands are:
store : Stores information about a person
lookup : Looks up a person from ID number
quit : Save changes and exit
? : Prints this message
Enter command(? for help)store
Enter unique ID number: 001
Enter name: Jim
Enter age: 10
Enter phone number: 19-221
Enter command(? for help)lookup
Enter ID number: 001
What would you like to know? (name,age,phone) name
Name: Jim
Enter command(? for help)lookup
Enter ID number: 001
What would you like to know? (name,age,phone) phone
Phone: 19-221
Enter command(? for help)quit