• python 内置方法、数据序列化


    abc(*args, **kwargs)

    取绝对值
    
    def add(a,b,f):
        return f(a)+f(b)
    res = add(3,-6,abs)
    print(res)

    all(*args, **kwargs)

    如果可迭代对象里面所有的元素都为真(非0),返回True
    可迭代对象为空,也返回True
    print( all([1,-5,3]) )
    print( all([0,-5,3]) )
    print(all([]))
    
    运行结果:
    True
    False
    True
    

    any(*args, **kwargs)

    如果可迭代对象里面任意的元素都为真(非0),返回True
    可迭代对象为空,也返回False
    print( any([]) )
    print( any([1,-5,3]) )
    print( any([0,-5,3]) )
    
    运行结果:
    False
    True
    True
    

    ascii(*args, **kwargs)

    Return an ASCII-only representation of an object.
    a= ascii([1,2,"开外挂开外挂"])
    print(type(a),[a])
    运行结果:
    <class 'str'> ["[1, 2, '\u5f00\u5916\u6302\u5f00\u5916\u6302']"]
    

    bin(*args, **kwargs)

    Return the binary representation of an integer.
    十进制转二进制
    print(bin(1))
    
    print(bin(3))
    print(bin(8))
    print(bin(255))
    
    运行结果:
    0b1
    0b11
    0b1000
    0b11111111
    

    bool(x)

    判断真假

    bytearray()

    字节和字符串不可修改,要修改,创建一个新的,在原有修改会覆盖
    
    bytearray()可修改的字节格式
    
    a = bytes("abcde",encoding="utf-8")
    b = bytearray("abcde",encoding="utf-8")
    print(a.capitalize(),a)
    print( b[1] )
    b[1]= 50
    print( b[1] )
    print(b)
    
    运行结果:
    b'Abcde' b'abcde'
    98
    50
    bytearray(b'a2cde')

    callable()

    是否可以调用
    
    def sayhi():pass
    print( callable(sayhi) )
    print( callable([]) )
    
    运行结果:
    True
    False
    

    chr(*args, **kwargs)

    返回ASCII码对应值
    print(chr(98))
    print(chr(87))
    
    运行结果:
    b
    W
    

    ord()

    输入的是ASCII码,与chr() 相反
    
    print(ord('?'))
    print(ord('@'))
    运行结果:
    63
    64
    

    complie(),exec()

    code = '''
    def fib(max): #10
        n, a, b = 0, 0, 1
        while n < max: #n<10
            #print(b)
            yield b
            a, b = b, a + b
            #a = b a =1, b=2, a=b , a=2,
            # b = a +b b = 2+2 = 4
            n = n + 1
        return '---done---'
    g = fib(6)
    for i in g:
        print(i)
    '''
    
    py_obj = compile(code,"err.log","exec")
    exec(py_obj)
    exec(code)
    

    dir()

    看字典里有什么方法
    >>> a= {}
    >>> dir(a)
    ['__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__get
    attribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt
    __', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setitem__', '__sizeof__', '__str__'
    , '__subclasshook__', 'clear', 'copy', 'fromkeys', 'get', 'items', 'keys', 'pop', 'popitem', 'setdefault', 'update', 'valu
    es']
    

    divmod(x, y)

    Return the tuple (x//y, x%y) ,(商,余数)
    
    >>> divmod(1,4)
    (0, 1)
    

    eval(*args, **kwargs)

    可以把字符变字典,字符里有控制语句的(如for),就得用exec
    a= "{1:'sadas'}"
    print(type(eval(a)),eval(a))
    x=1
    print(eval("x+1+3"))
    
    运行结果:
    <class 'dict'> {1: 'sadas'}
    5
    

    filter(function,iterable)

    先学习一下 匿名函数
    
    def sayhi(n):
        print(n)
    
    sayhi(5)
    
    
    (lambda n:print(n))(5)
    calc = lambda n:3 if n<4 else n
    print(calc(2))
    运行结果:
    
    
    filter()一组数据中过滤出你想要的
    
    res = filter(lambda n:n>5,range(10))
    print(res)  #变成一个迭代器
    for i in res:
        print(i)
    
    运行结果:
    <filter object at 0x0000018F692BB080>
    
    
    map()
    
    res = map(lambda n:n*2,range(10))  # [i * 2 for i in range(10)]    ,  res = [ lambda i:i*2 for i in range(10)]
    print(res)
    for j in res:
        print(j)
    运行结果:
    0
    2
    4
    6
    8
    10
    12
    14
    16
    18

    frozenset()

    >>> set2 = frozenset(set1)
    >>> set2
    frozenset({3, 4, 5})
    >>> set2.remove(2)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    AttributeError: 'frozenset' object has no attribute 'remove'
    不可变集合
    a = frozenset([1,4,333,212,33,33,12,4])
    

    globals(*args, **kwargs)

    返回当前程序所有变量的key,value
    Return the dictionary containing the current scope's global variables.
    
    print(globals())
    
    运行结果:
    {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000001E64F79B048>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, '__file__': 'D:/PycharmProjects/python_code_scq/04_week_code/内置方法.py', '__cached__': None, '__author__': 'sunchengquan', '__mail__': '1641562360@qq.com'}
    

    hex()

    转十六进制
    >>> hex(2)
    '0x2'
    >>> hex(10)
    '0xa'
    >>> hex(15)
    '0xf'
    >>> hex(600)
    '0x258'
    

    id()

    返回内存地址

    locals(*args, **kwargs)

    def test():
        local_var =333
        print(locals())
        print(globals())
    test()
    print(globals())
    print(globals().get('local_var'))
    
    运行结果:
    {'local_var': 333}
    {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000001E7C63BB048>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, '__file__': 'D:/PycharmProjects/python_code_scq/04_week_code/内置方法.py', '__cached__': None, '__author__': 'sunchengquan', '__mail__': '1641562360@qq.com', 'test': <function test at 0x000001E7C6013E18>}
    {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000001E7C63BB048>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, '__file__': 'D:/PycharmProjects/python_code_scq/04_week_code/内置方法.py', '__cached__': None, '__author__': 'sunchengquan', '__mail__': '1641562360@qq.com', 'test': <function test at 0x000001E7C6013E18>}
    None
    

    oct()

    转八进制
    >>> oct(7)
    '0o7'
    >>> oct(8)
    '0o10'
    >>> oct(9)
    '0o11'
    

    pow()

    Equivalent to x**y (with two arguments) or x**y % z (with three arguments)
    >>> pow(3,3)
    27
    >>> pow(2,3)
    8
    >>> pow(2,8)
    256
    

    sorted(*args, **kwargs)

    a = {6:2,8:0,1:4,-5:6,99:11,4:22}
    print(sorted(a))
    print(sorted(a.items())) #按key排序
    print(sorted(a.items(),key=lambda x:x[1]))# 按value 排序
    
    运行结果:
    [-5, 1, 4, 6, 8, 99]
    [(-5, 6), (1, 4), (4, 22), (6, 2), (8, 0), (99, 11)]
    [(8, 0), (6, 2), (1, 4), (-5, 6), (99, 11), (4, 22)]
    

    zip()

    a = [1,2,3,4,5,6]
    b = ['a','b','c','d']
    for i in zip(a,b):
        print(i)
    
    运行结果:
    (1, 'a')
    (2, 'b')
    (3, 'c')
    (4, 'd')
    

    import()

    __import__('decorator')


    Json & pickle 数据序列化

    序列化1:

    a={'a':'a1','b':'b1'}
    b=open('ceshi.txt','w')
    b.write(str(a))

    {'a': 'a1', 'b': 'b1'}

    反序列化:

    b=open('ceshi.txt','r')
    a=b.read()
    print a
    
    >>{'a': 'a1', 'b': 'b1'}
    

    b=open('ceshi.txt','r')
    print eval(b.read())

    {'a': 'a1', 'b': 'b1'}

    序列化2:

    import json
    a={'a':'a1','b':'b1'}
    b=open('ceshi.txt','w')
    b.write(json.dumps(a))
    
    
    {"a": "a1", "b": "b1"}
    

    反序列化:

    import json
    b=open('ceshi.txt','r')
    print json.loads(b.read())
    
    
    {u'a': u'a1', u'b': u'b1'}
    

     

     




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  • 原文地址:https://www.cnblogs.com/iexperience/p/9079412.html
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