python对象基本用法

>>> -4
-4
>>> 2
2
>>> 10000000000000000000000000000000
10000000000000000000000000000000L
>>> 1.23
1.23
>>> 53E-4
0.0053
>>> 3+4j
(3+4j)
>>> 076
62
>>> 0xaf
175
>>> 4+3
7
>>> 4-1
3
>>> 4*5
20
>>> 5/2
2
>>> 5%2
1
>>> 5>>1
2
>>> 5^3
6
>>> 5%2
1
>>> 5|2
7
>>> import math
>>> dir(math)
[‘__doc__‘, ‘__name__‘, ‘acos‘, ‘asin‘, ‘atan‘, ‘atan2‘, ‘ceil‘, ‘cos‘, ‘cosh‘, ‘degrees‘, ‘e‘, ‘exp‘, ‘fabs‘,
 ‘floor‘, ‘fmod‘, ‘frexp‘, ‘hypot‘, ‘ldexp‘, ‘log‘, ‘log10‘, ‘modf‘, ‘pi‘, ‘pow‘, ‘radians‘, ‘sin‘, ‘sinh‘, ‘sqrt‘, ‘tan‘, ‘tanh‘]
>>> abs
<built-in function abs>
>>> abs(-4)
4
>>> import random
>>> random.random()
0.39950530297297382

>>> s1=‘aaaaa"aaaa‘
>>> s2="bbbbb‘bbbb"
>>> s3=‘‘‘aa‘bb"dd‘‘‘
>>> s4="""a‘‘‘dd‘‘‘cc‘dd"ff"ggg"""
>>> s1+s2
"aaaaaaaaabbbbb‘bbbb"
>>> s1*3
‘aaaaa"aaaaaaaaa"aaaaaaaaa"aaaa‘
>>> s3[3]
‘b‘
>>> s3[1:4]
"a‘b"
>>> s3[:4]
"aa‘b"
>>> s3[4:]
‘b"dd‘
>>> s3[1:-2]
‘a\‘bb"‘
>>> s3[-2]
‘d‘
>>> len(s3)
8
>>> "a=%s%d"%(‘bb‘,4)
‘a=bb4‘
>>> for x in s2:print x
... 
b
b
b
b
b
‘
b
b
b
b
>>> ‘aaa‘ in s1
True
>>> dir(s1)
[‘__add__‘, ‘__class__‘, ‘__contains__‘, ‘__delattr__‘, ‘__doc__‘, ‘__eq__‘, ‘__ge__‘, ‘__getattribute__‘,
 ‘__getitem__‘, ‘__getnewargs__‘, ‘__getslice__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__le__‘, ‘__len__‘,
 ‘__lt__‘, ‘__mod__‘, ‘__mul__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘,
 ‘__rmod__‘, ‘__rmul__‘, ‘__setattr__‘, ‘__str__‘, ‘capitalize‘, ‘center‘, ‘count‘, ‘decode‘,
 ‘encode‘, ‘endswith‘, ‘expandtabs‘, ‘find‘, ‘index‘, ‘isalnum‘, ‘isalpha‘, ‘isdigit‘, ‘islower‘,
 ‘isspace‘, ‘istitle‘, ‘isupper‘, ‘join‘, ‘ljust‘, ‘lower‘, ‘lstrip‘, ‘replace‘, ‘rfind‘, ‘rindex‘,
 ‘rjust‘, ‘rsplit‘, ‘rstrip‘, ‘split‘, ‘splitlines‘, ‘startswith‘, ‘strip‘, ‘swapcase‘, ‘title‘, ‘translate‘, ‘upper‘, ‘zfill‘]
>>> import string
>>> dir(string)
[‘Template‘, ‘_TemplateMetaclass‘, ‘__builtins__‘, ‘__doc__‘, ‘__file__‘, ‘__name__‘, ‘_float‘, ‘_idmap‘,
 ‘_idmapL‘, ‘_int‘, ‘_long‘, ‘_multimap‘, ‘_re‘, ‘ascii_letters‘, ‘ascii_lowercase‘, ‘ascii_uppercase‘,
 ‘atof‘, ‘atof_error‘, ‘atoi‘, ‘atoi_error‘, ‘atol‘, ‘atol_error‘, ‘capitalize‘, ‘capwords‘, ‘center‘,
 ‘count‘, ‘digits‘, ‘expandtabs‘, ‘find‘, ‘hexdigits‘, ‘index‘, ‘index_error‘, ‘join‘, ‘joinfields‘,
 ‘letters‘, ‘ljust‘, ‘lower‘, ‘lowercase‘, ‘lstrip‘, ‘maketrans‘, ‘octdigits‘, ‘printable‘, ‘punctuation‘,
 ‘replace‘, ‘rfind‘, ‘rindex‘, ‘rjust‘, ‘rsplit‘, ‘rstrip‘, ‘split‘, ‘splitfields‘, ‘strip‘, ‘swapcase‘,
 ‘translate‘, ‘upper‘, ‘uppercase‘, ‘whitespace‘, ‘zfill‘]
>>> s5=‘\‘\"\n\044‘
>>> s5
‘\‘"\n$‘

>>> t1=()
>>> t2=(2,35)
>>> dir(t2)
[‘__add__‘, ‘__class__‘, ‘__contains__‘, ‘__delattr__‘, ‘__doc__‘, ‘__eq__‘, ‘__ge__‘, ‘__getattribute__‘, ‘__getitem__‘, ‘__getnewargs__‘, ‘__getslice__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__iter__‘, ‘__le__‘, ‘__len__‘, ‘__lt__‘, ‘__mul__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__rmul__‘, ‘__setattr__‘, ‘__str__‘]
>>> len(t2)
2
>>> t2+t1
(2, 35)

>>> l1=[1,2,4]
>>> l2=[1,‘aa‘,[3,4],{‘b‘:‘ccc‘}]
>>> l2[1]
‘aa‘
>>> l2[2:4]
[[3, 4], {‘b‘: ‘ccc‘}]
>>> l2+l1
[1, ‘aa‘, [3, 4], {‘b‘: ‘ccc‘}, 1, 2, 4]
>>> l2.sort()
>>> l2
[1, {‘b‘: ‘ccc‘}, [3, 4], ‘aa‘]
>>> len(l2)
4
>>> l2[-2]
[3, 4]
>>> l1.insert(1,‘aaa‘)
>>> l1
[1, ‘aaa‘, 2, 4]
>>> l1.append(‘bbbb‘)
>>> l1
[1, ‘aaa‘, 2, 4, ‘bbbb‘]
>>> del l1[1]
>>> l1
[1, 2, 4, ‘bbbb‘]
>>> del l1[2:]
>>> l1
[1, 2]
>>> dir(l1)
[‘__add__‘, ‘__class__‘, ‘__contains__‘, ‘__delattr__‘, ‘__delitem__‘, ‘__delslice__‘, ‘__doc__‘, ‘__eq__‘,
 ‘__ge__‘, ‘__getattribute__‘, ‘__getitem__‘, ‘__getslice__‘, ‘__gt__‘, ‘__hash__‘, ‘__iadd__‘, ‘__imul__‘,
 ‘__init__‘, ‘__iter__‘, ‘__le__‘, ‘__len__‘, ‘__lt__‘, ‘__mul__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘,
 ‘__reduce_ex__‘, ‘__repr__‘, ‘__reversed__‘, ‘__rmul__‘, ‘__setattr__‘, ‘__setitem__‘, ‘__setslice__‘,
 ‘__str__‘, ‘append‘, ‘count‘, ‘extend‘, ‘index‘, ‘insert‘, ‘pop‘, ‘remove‘, ‘reverse‘, ‘sort‘]
>>> for x in l2:print x
... 
1
{‘b‘: ‘ccc‘}
[3, 4]
aa
>>> l3=l2
>>> l3
[1, {‘b‘: ‘ccc‘}, [3, 4], ‘aa‘]
>>> del l2[1]
>>> l2
[1, [3, 4], ‘aa‘]
>>> l3
[1, [3, 4], ‘aa‘]

>>> d1={}
>>> d2={‘aa‘:‘bbb‘,2:‘rrr‘,‘tt‘:[2,3],‘dd‘:{2:4}}
>>> d3={‘中文‘:‘fffffff‘}
>>> d3
{‘\xd6\xd0\xce\xc4‘: ‘fffffff‘}
>>> d2[‘aa‘]
‘bbb‘
>>> dir(d1)
[‘__class__‘, ‘__cmp__‘, ‘__contains__‘, ‘__delattr__‘, ‘__delitem__‘, ‘__doc__‘, ‘__eq__‘, ‘__ge__‘, ‘__getattribute__‘,
 ‘__getitem__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__iter__‘, ‘__le__‘, ‘__len__‘, ‘__lt__‘, ‘__ne__‘, ‘__new__‘,
 ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__setattr__‘, ‘__setitem__‘, ‘__str__‘, ‘clear‘, ‘copy‘, ‘fromkeys‘,
 ‘get‘, ‘has_key‘, ‘items‘, ‘iteritems‘, ‘iterkeys‘, ‘itervalues‘, ‘keys‘, ‘pop‘, ‘popitem‘, ‘setdefault‘, ‘update‘, ‘values‘]
>>> for key in d2:print d2[key]
... 
bbb
rrr
{2: 4}
[2, 3]
>>> d4=d2
>>> del d2[‘aa‘]
>>> d4
{2: ‘rrr‘, ‘dd‘: {2: 4}, ‘tt‘: [2, 3]}
>>> d5=d2.copy()
>>> del d2[‘dd‘]
>>> d5
{2: ‘rrr‘, ‘tt‘: [2, 3], ‘dd‘: {2: 4}}
>>> d5[‘mm‘] = 9
>>> d5
{‘mm‘: 9, 2: ‘rrr‘, ‘tt‘: [2, 3], ‘dd‘: {2: 4}}

>>> s1=set([])
>>> s2=set([1,2,3])   #无序不重复元素集
>>> s3=set([2,‘ddd‘])
>>> dir(s1)
[‘__and__‘, ‘__class__‘, ‘__cmp__‘, ‘__contains__‘, ‘__delattr__‘, ‘__doc__‘, ‘__eq__‘, ‘__ge__‘, ‘__getattribute__‘,
 ‘__gt__‘, ‘__hash__‘, ‘__iand__‘, ‘__init__‘, ‘__ior__‘, ‘__isub__‘, ‘__iter__‘, ‘__ixor__‘, ‘__le__‘, ‘__len__‘,
 ‘__lt__‘, ‘__ne__‘, ‘__new__‘, ‘__or__‘, ‘__rand__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__ror__‘, ‘__rsub__‘,
 ‘__rxor__‘, ‘__setattr__‘, ‘__str__‘, ‘__sub__‘, ‘__xor__‘, ‘add‘, ‘clear‘, ‘copy‘, ‘difference‘, ‘difference_update‘,
 ‘discard‘, ‘intersection‘, ‘intersection_update‘, ‘issubset‘, ‘issuperset‘, ‘pop‘, ‘remove‘, ‘symmetric_difference‘,
 ‘symmetric_difference_update‘, ‘union‘, ‘update‘]
>>> ‘ddd‘ in s3
True
>>> s3-s2
set([‘ddd‘])
>>> s3|s2
set([1, 2, 3, ‘ddd‘])
>>> s3&s2
set([2])
>>> s3^s2
set([1, 3, ‘ddd‘])