python中类的用法与脚本的用法

类

实例：

#!/usr/bin/env python
# -*- coding=utf-8 -*-

class MyClass:
	""" simple   """
	i = 12
	def say(self):
		print "hello"
		return "hello,world"

class Pet(object):
	def __init__(self,name,species):
		self.name = name
		self.species = species

	def getName(self):
		return self.name

	def getSpecies(self):
		return species

	def __str__(self):
		return "%s is a %s" % (self.name,self.species)

if __name__ == "__main__":
	x = MyClass()
	x.say()
	print x.i

	print "========="

	polly = Pet("polly","cat")
	print polly
	harry = Pet("harry","dog")
	print harry.getName()

脚本

SUFFIXES = {1000: ['KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'],
            1024: ['KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB']}

def approximate_size(size, a_kilobyte_is_1024_bytes=True):
    '''Convert a file size to human-readable form.

    Keyword arguments:
    size -- file size in bytes
    a_kilobyte_is_1024_bytes -- if True (default), use multiples of 1024
                                if False, use multiples of 1000

    Returns: string

    '''
    if size < 0:
        raise ValueError('number must be non-negative')

    multiple = 1024 if a_kilobyte_is_1024_bytes else 1000
    for suffix in SUFFIXES[multiple]:
        size /= multiple
        if size < multiple:
            return '{0:.1f} {1}'.format(size, suffix)

    raise ValueError('number too large')

if __name__ == '__main__':
    print(approximate_size(1000000000000, False))
    print(approximate_size(1000000000000))

init等内置函数

init(self,…) 初始化对象，创建新对象时调用
del(self) 释放对象，在对象被删除之前调用
new(cls,*args,**kwd) 实例的生成操作
str(self) 使用print语句时被调用
getitem(self,key) 获取序列的索引key对应的值，等价于seq[key]
len(self) 在调用内联函数len()时被调用
cmp(stc,dst) 比较两个对象src和dst
getattr(s,name) 获取属性的值
setattr(s,name,value) 设置属性的值
delattr(s,name) 删除name属性
getattribute() getattribute()与__getattr__()类似
gt(self,other) 判断self对象是否大于other对象
lt(self,other) 判断self对象是否小于other对象
ge(self,other) 判断self对象是否大于或等于other对象
le(self,other) 判断self对象是否小于或等于other对象
ep(self,other) 判断self对象是否等于other对象
call(self,*args) 把实例对象作为函数调用

name==”main”

Example

		
#!/usr/bin/python
# Filename: using_name.py

if __name__ == '__main__':
	print 'This program is being run by itself'
else:
	print 'I am being imported from another module'

Output

			
$ python using_name.py
This program is being run by itself

$ python
>>> import using_name
I am being imported from another module
>>>

How It Works? 每个python模块均有__name__这个属性，如果该属性为__main__,意味着该模块以单例模式被用户运行，我们可以采取相对应待合适的措施。

类

脚本

__init__等内置函数

name==”main”

init等内置函数