import module
from module import func
from module import func1, func2, ...
from module import * # 导入所有函数
# 使用不同模块的同名函数
module1.open()
module2.open()
# 为模块起别名
import math as foobar
print foobar.sqrt(9.0)
# 为函数起别名
from math import sqrt as foobar
print foobar(9.0)
赋值
序列解包
x, y, z = 1, 2, 3
print x, y, z # 1 2 3
x, y = y, x # swap x, y
values = 1, 2, 3
print values # (1, 2, 3)
x, y, z = values
print x # 1 # FIXME: values的len必须和左边的变量数量一致
# 链式赋值
# import somemodule
# from somemodule import somefunction
# from somemodule import somefunction, anotherfunction...
# from somemodule import *
import math as foobar
print foobar.sqrt(4)
from math import sqrt as foobar
print foobar(4)
# sequence unpacking
x, y, z = 1, 2, 3
print x, y, z # 1, 2, 3
x, y = y, x
print x, y, z # 2, 1, 3
values = 1, 2, 3
print values
x, y, z = values
print x, y, z # 1, 2, 3
scoundrel = {"name": "Robin", "girlfriend": "Marion"}
key, value = scoundrel.popitem()
print key, value
# following both will throw exception
# x, y, z = 1, 2
# x, y, z = 1, 2, 3, 4
import math from cmath import sqrt x = math.floor(21.9) print x y = int(math.floor(21.9)) print y z = sqrt(-1) print z w = (1 + 3j) * (2 + 4J) print w # import somemoudle # from somemoudle import somefunction # from somemoudle import somefunction anothersomefunction yetanothersomefunction # from somemoudle import * import math as foobar foobar.sqrt(4) from math import sqrt as foobar foobar(4)
import math as foobar
print foobar.sqrt(4)
from math import sqrt as foobar
print foobar(4)
# nice formate of python
x, y, z = 3, 4, 10
print y, z, x
x, y = y, x
print x, y, z
# more explicit
print "more interesting "
values = 1, 2, 3
print values
x, y, z = values
print y
scundrel = {'name': 'Emon', 'boyFriend': 'sobuj'}
key, value = scundrel.popitem()
print 'popitem using by ', key
print 'value is ', value
print('Age: ', 24)
print(1, 2, 3)
print((1, 2, 3))
name = 'Gumby'
salutation = 'Mr.'
greeting = 'Hello,'
print(greeting, salutation, name)
greeting = 'Hello'
print(greeting, ',', salutation, name)
print(greeting + ',', salutation, name)
print('Hello'),
print('world!')
import math as foobar
foobar.sqrt(4)
from math import sqrt as foobar
foobar(4)
# 解包
x, y, z = 1, 2, 3
print(x, y, z)
x, y = y, z
print(x, y, z)
scoundrel = {'name': 'Robin', 'girlfriend': 'Marion'}
key, value = scoundrel.popitem()
print(key),
print(value)
# 解包 新
a, b, *rest = [1, 2, 3, 4]
x = y = people.get('mlh')
#等价于
'''evil with the import statement'''
import sys
def foo_func(x):
return x * x
sys.modules['foobar'] = foo_func
import foobar
print foobar(10)
class Klass(object):
'''a classy class'''
def bar(self, x):
return x * x * x
sys.modules['classy'] = Klass
import classy
print classy().bar(10)
sys.modules['yarr'] = Klass()
import yarr
print yarr.bar(10)
from somemodule import *
#如果两个模块都有open函数，就需要像下面这样使用函数
module1.open(...)
module2.open(...)
# 或，在语句末尾增加一个as子句，在该as子句后给出的名字，将
# 成为整个模块的别名
import math as foobar
foobar.sqrt(4)
# 同样可以为函数提供别名
from math import sqrt as foobar
foobar(9)
#序列解包（sequence unpacking），可选代解包
x,y,z = 1,2,3
print x, y, z
x,y = y,x
print x, y
scoundrel = {'name':'robin', 'girlfriend':'marion'}
key, value = scoundrel.popitem()
print key, value
# 需要注意的是，所解包的序列中的元素数量必须和放置在赋值符号=左边的变量数量
# 完全一致，否则python会赋值时引发异常
或者 from somemodule import somefunction 或者 from somemodule import somefunction,anotherfunction,yetanotherfunction 或者 from somemodule import * 只有确定自己想要从给定的模块导入所有功能时，才应该使用最后一个版本。但是如果两个模块都有open函数，那又该怎么办？只需使用第一种方式导入，然后像下面这样使用函数: module1.open(...) module2.open(...) 但还有另外的选择：可以在语句末尾增加一个as子句，在该子句后给出名字，或为整个模块提供别名： >>> import math as foobar >>> foobar.sqrt(4) 2.0 也可以为函数提供别名： >>> from math import sqrt as foobar >>> foobar(4) 2.0 对于open函数，可以像下面这样使用: from module1 import open as open1 from module2 import open as open2 注意：有些模块，例如os.path是分层次安排的(一个模块在另一个模块的内部). 就算是不起眼的赋值语句也有一些特殊的技巧 序列解包 赋值语句的例子已经给过不少，其中包括对变量和数据结构成员的(比如列表中的位置和分片以及字典中的槽)赋值。但赋值的方法还不止这些。比如，多个赋值操作可以同时进行： >>> x,y,z=1,2,3 >>> print x,y,z 1 2 3 >>> x,y=y,x >>> print x,y,z 事实上，这里所做的事情叫做序列解包或可选代解包-将多个值的序列解开，然后放到变量的序列中。更形象一点的表示出来就是： >>> values=1,2,3
'''evil with the import statement'''
import sys
def foo_func(x):
return x * x
sys.modules['foobar'] = foo_func
import foobar
print foobar(10)
class Klass(object):
'''a classy class'''
def bar(self, x):
return x * x * x
sys.modules['classy'] = Klass
import classy
print classy().bar(10)
sys.modules['yarr'] = Klass()
import yarr
print yarr.bar(10)
sys.modules['argh'] = Klass().bar
