一、作用域
只要变量在内存中存在，则就可以使用.（栈）
二、三元运算
result = 值
result = 值1 if 条件 else 值2
如果条件为真：result = 值1
如果条件为假：result = 值2
三、帮助用法
type 查看对象的类型
dir(类型名) 查看类中提供的所有功能
help(类型名) 查看类中所有详细功能
help(类型名.功能名) 查看类中某一个功能的详细
类中的方法：
__方法__ 内置方法 ,可能有多种执行方法，至少一种
方法 非内置方法 的执行只有一种
四、函数
divmod(a,b)函数
中文说明：
divmod(a,b)方法返回的是a//b（除法取整）以及a对b的余数
find()函数
find 找不到 -1
index 报错
五、字符串格式化
name = 'i am {0},age {1}'
name.format('alex',19)
name = 'i am {ss},age {dd}'
name.format(ss='alex',dd=80)
li = [1,2]
name = 'i am {0},age {1}'
name.format(*li)
dic = {'ss':123,'dd':456}
name = 'i am {ss},age {dd}'
name.format(**dic)
截取字符串,如果索引为负数，就是相当于从后向前数,下标可以为空表示取到头或尾
a = 'a1aa2'
a[0:1] [左包含，右不包含]
a[0:-1]
a[0:]
import string
intab = "aeiou"
outtab = "12345"
trantab = string.maketrans(intab, outtab)
str = "this is string example....wow!!!"
print str.translate(trantab, 'xm')
六、列表的功能
list.append(obj) # 向列表中添加一个对象obj
list.count(obj) # 返回一个对象obj在列表中出现的次数
list.extend(seq) # 把序列seq的内容添加到列表中
list.index(obj,i=0,j=len(list)) # 返回list[k] == obj 的k值,并且k的范围在i<=k<j;否则异常 （##取出在列表中的位置）
list.insert(index,obj) # 在索引量为index的位置插入对象obj
list.pop(index=-1) # 删除并返回指定位置的对象,默认是最后一个对象 (##删除时按照下标删除)
list.remove(obj) # 从列表中删除对象obj (##删除时按照内容删除,只删除第一个出现的)
list.reverse() # 原地翻转列表
list.sort(func=None,key=None,reverse=False) # 以指定的方式排序列表中成员,如果func和key参数指定,则按照指定的方式比较各个元素,如果reverse标志被置为True,则列表以反序排列
字母按照asic 中文按照unicode
七、元组
元组的元素不能被修改，元素的元素可以被修改。
八、字典的功能
dict.clear() # 删除字典中所有元素
dict copy() # 返回字典(浅复制)的一个副本
dict.fromkeys(seq,val=None) # 创建并返回一个新字典,以seq中的元素做该字典的键,val做该字典中所有键对的初始值
dict.get(key,default=None) # 对字典dict中的键key,返回它对应的值value,如果字典中不存在此键,则返回默认值
dict.has_key(key) # 如果键在字典中存在,则返回True 用in和not in代替
dicr.items() # 返回一个包含字典中键、值对元组的列表
dict.keys() # 返回一个包含字典中键的列表
dict.iter() # 方法iteritems()、iterkeys()、itervalues()与它们对应的非迭代方法一样,不同的是它们返回一个迭代子,而不是一个列表
dict.pop(key[,default]) # 和方法get()相似.如果字典中key键存在,删除并返回dict[key]
dict.setdefault(key,default=None) # 和set()相似,但如果字典中不存在key键,由dict[key]=default为它赋值
dict.update(dict2) # 将字典dict2的键值对添加到字典dict
dict.values() # 返回一个包含字典中所有值得列表
九、set集合
set是一个无序且不重复的元素集合
class set(object):
"""
set() -> new empty set object
set(iterable) -> new set object Build an unordered collection of unique elements.
"""
def add(self, *args, **kwargs): # real signature unknown
""" 添加 """
"""
Add an element to a set. This has no effect if the element is already present.
"""
pass def clear(self, *args, **kwargs): # real signature unknown
""" Remove all elements from this set. """
pass def copy(self, *args, **kwargs): # real signature unknown
""" Return a shallow copy of a set. """
pass def difference(self, *args, **kwargs): # real signature unknown
"""
Return the difference of two or more sets as a new set. (i.e. all elements that are in this set but not the others.)
"""
pass def difference_update(self, *args, **kwargs): # real signature unknown
""" 删除当前set中的所有包含在 new set 里的元素 """
""" Remove all elements of another set from this set. """
pass def discard(self, *args, **kwargs): # real signature unknown
""" 移除元素 """
"""
Remove an element from a set if it is a member. If the element is not a member, do nothing.
"""
pass def intersection(self, *args, **kwargs): # real signature unknown
""" 取交集，新创建一个set """
"""
Return the intersection of two or more sets as a new set. (i.e. elements that are common to all of the sets.)
"""
pass def intersection_update(self, *args, **kwargs): # real signature unknown
""" 取交集，修改原来set """
""" Update a set with the intersection of itself and another. """
pass def isdisjoint(self, *args, **kwargs): # real signature unknown
""" 如果没有交集，返回true """
""" Return True if two sets have a null intersection. """
pass def issubset(self, *args, **kwargs): # real signature unknown
""" 是否是子集 """
""" Report whether another set contains this set. """
pass def issuperset(self, *args, **kwargs): # real signature unknown
""" 是否是父集 """
""" Report whether this set contains another set. """
pass def pop(self, *args, **kwargs): # real signature unknown
""" 移除 """
"""
Remove and return an arbitrary set element.
Raises KeyError if the set is empty.
"""
pass def remove(self, *args, **kwargs): # real signature unknown
""" 移除 """
"""
Remove an element from a set; it must be a member. If the element is not a member, raise a KeyError.
"""
pass def symmetric_difference(self, *args, **kwargs): # real signature unknown
""" 差集，创建新对象"""
"""
Return the symmetric difference of two sets as a new set. (i.e. all elements that are in exactly one of the sets.)
"""
pass def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
""" 差集，改变原来 """
""" Update a set with the symmetric difference of itself and another. """
pass def union(self, *args, **kwargs): # real signature unknown
""" 并集 """
"""
Return the union of sets as a new set. (i.e. all elements that are in either set.)
"""
pass def update(self, *args, **kwargs): # real signature unknown
""" 更新 """
""" Update a set with the union of itself and others. """
pass def __and__(self, y): # real signature unknown; restored from __doc__
""" x.__and__(y) <==> x&y """
pass def __cmp__(self, y): # real signature unknown; restored from __doc__
""" x.__cmp__(y) <==> cmp(x,y) """
pass def __contains__(self, y): # real signature unknown; restored from __doc__
""" x.__contains__(y) <==> y in x. """
pass def __eq__(self, y): # real signature unknown; restored from __doc__
""" x.__eq__(y) <==> x==y """
pass def __getattribute__(self, name): # real signature unknown; restored from __doc__
""" x.__getattribute__('name') <==> x.name """
pass def __ge__(self, y): # real signature unknown; restored from __doc__
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y): # real signature unknown; restored from __doc__
""" x.__gt__(y) <==> x>y """
pass def __iand__(self, y): # real signature unknown; restored from __doc__
""" x.__iand__(y) <==> x&=y """
pass def __init__(self, seq=()): # known special case of set.__init__
"""
set() -> new empty set object
set(iterable) -> new set object Build an unordered collection of unique elements.
# (copied from class doc)
"""
pass def __ior__(self, y): # real signature unknown; restored from __doc__
""" x.__ior__(y) <==> x|=y """
pass def __isub__(self, y): # real signature unknown; restored from __doc__
""" x.__isub__(y) <==> x-=y """
pass def __iter__(self): # real signature unknown; restored from __doc__
""" x.__iter__() <==> iter(x) """
pass def __ixor__(self, y): # real signature unknown; restored from __doc__
""" x.__ixor__(y) <==> x^=y """
pass def __len__(self): # real signature unknown; restored from __doc__
""" x.__len__() <==> len(x) """
pass def __le__(self, y): # real signature unknown; restored from __doc__
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y): # real signature unknown; restored from __doc__
""" x.__lt__(y) <==> x<y """
pass @staticmethod # known case of __new__
def __new__(S, *more): # real signature unknown; restored from __doc__
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y): # real signature unknown; restored from __doc__
""" x.__ne__(y) <==> x!=y """
pass def __or__(self, y): # real signature unknown; restored from __doc__
""" x.__or__(y) <==> x|y """
pass def __rand__(self, y): # real signature unknown; restored from __doc__
""" x.__rand__(y) <==> y&x """
pass def __reduce__(self, *args, **kwargs): # real signature unknown
""" Return state information for pickling. """
pass def __repr__(self): # real signature unknown; restored from __doc__
""" x.__repr__() <==> repr(x) """
pass def __ror__(self, y): # real signature unknown; restored from __doc__
""" x.__ror__(y) <==> y|x """
pass def __rsub__(self, y): # real signature unknown; restored from __doc__
""" x.__rsub__(y) <==> y-x """
pass def __rxor__(self, y): # real signature unknown; restored from __doc__
""" x.__rxor__(y) <==> y^x """
pass def __sizeof__(self): # real signature unknown; restored from __doc__
""" S.__sizeof__() -> size of S in memory, in bytes """
pass def __sub__(self, y): # real signature unknown; restored from __doc__
""" x.__sub__(y) <==> x-y """
pass def __xor__(self, y): # real signature unknown; restored from __doc__
""" x.__xor__(y) <==> x^y """
pass __hash__ = None set
十、深浅拷贝
为什么要拷贝？
当进行修改时，想要保留原来的数据和修改后的数据
数字字符串 和 集合 在修改时的差异？ （深浅拷贝不同的终极原因）
在修改数据时：
数字字符串：在内存中新建一份数据
集合：修改内存中的同一份数据
对于集合，如何保留其修改前和修改后的数据？
在内存中拷贝一份
对于集合，如何拷贝其n层元素同时拷贝？
深拷贝