Python3 内置函数

本文由 Luzhuo 编写,转发请保留该信息.
原文: http://blog.csdn.net/Rozol/article/details/70603230

#coding=utf-8# builtin_function.py 内置函数import osdef fun():    all([True, False]) # 迭代器(为空or)所有元素为true,返回true => False    any([True, False]) # 迭代器任意一个元素为true,返回true => True    num = abs(-1.23) # 绝对值    num = pow(5, 3) # 幂次方 x**y =>125    num = pow(5, 3, 3) # 幂次方再取余 (x**y) % z => 2    num = round(1.23) # 返回浮点数近似值,默认保留0位,且四舍五入    num = round(1.23, 5) # 5为保留小数点后位数    num = sum([1, 2, 3, 4, 5]) # 对列表数字求和    strs = ascii(os) # 返回对象的ascii字符串形式    strs = bin(123) # 整数转为二进制字符串(若被转对象非int类型可在__index__里定义)    boolean = bool(0) # 获取真假(假:None / False / 任何类型的0 / 空""()[]{} / __bool__返回False / __len__返回0)    bytes = bytearray("You were, are and will be in my heart!", "utf-8") # 字符串(字符串,编码):按编码转为字节序列 / 数字(数字):生成相应大小的空数组 / 无参():0数组    bytes = bytes("You were, are and will be in my heart!", "utf-8") # 同bytearray(),但是不可变    strs = chr(123) # 整数(Unicode)转为char类型(范围[0, 1 114 111])    num = ord("{") # char类型转为整数(Unicode)    num = complex("1+2j") # 将字符串或数字转为复数(不能含有空格)    num = float('1.1') # 构建浮点数    strs = format(123,'f') # 格式化(类型:x,b,f... / 位移:>(>10),<,^ / 长度:5 / E)    strs = hex(123) # 将整数转为16进制字符串    strs = oct(123) # 十进制转成8进制字符串    num = int(123.1) # 转为整数    strs = str(123) # 将对象转为字符串    strs = str(b"123", "utf-8")    elem = max([1,2,3,4], [2,4,6]) # 可接收1个iterable,或多个元素 => [2, 4, 6]    elem = max(1,2,3,4) # => 4    elem = max([1,2,3,4, 6], key = lambda x : x == 2) # => 2    elem = min(1,2,3,4) # 与max相反    exe = compile("print('O_O')", filename = 'strs', mode='exec') # 编译为代码, mode(编译模式:可执行语句'exec',单个语句'eval',交互式语句'single')    exec(exe) # 执行已编译代码    exec("print('O_O')") # 执行String未编译代码    eval(compile("print('O_O')", filename = 'strs', mode='eval')) # 不接受字符串类型    delattr(Clazz("Hello!"), "name") # 删除某对象属性 = del clazz.name 详情见 类 文章的 反射 代码块(http://blog.csdn.net/rozol/article/details/69317339)    setattr(Clazz("Hello!"), "name", "World!") # 给对象某属性赋值    strs = getattr(Clazz("Hello!"), "name") # 获取某个对象的属性值    strs = getattr(Clazz("Hello!"), "name", -1) # -1为未找到属性的返回    boolean = hasattr(Clazz("Hello!"), "name") # 该对象是否有该属性    lists = dir(Clazz("Hello!"))  # 查看函数    clazz = type(os) # 获取类型    dicts = globals() # 获取当前全局函数与对象    dicts = locals() # 获取当前局部函数与对象    dicts = vars() # 同locals() (__dict__)    dicts = vars(Clazz("Hello!"))    num = hash(Clazz("Hello!")) # 获取某对象的hash值     help(os) # 获取某对象的帮助文档    num = id(os) # 获取某对象的id    boolean = isinstance(Clazz("Hello!"), Clazz) # 对象是否是该类的实例    boolean = issubclass(Clazz, Clazz) # 该类(前)是否是该类(后)的子类(包括自己)    strs = repr(os) # 将对象转为字符串表达形式    # - super() # 代理父类对象,详情见 类 文章(http://blog.csdn.net/rozol/article/details/69317339)    # - memoryview(obj) # 内存视图,详解 数据结构 文章(http://blog.csdn.net/rozol/article/details/68938984)    dics = dict() # 创建字典    tups = divmod(10, 5) # 返回元组,(商(10/5),余数(10%5))    lists = enumerate(['a', 'b', 'c']) # 返回枚举对象    lists = filter(lambda x: True if (ord(x) > 66) else False, ['a', 'b', 'c']) # function为Frue保留,False移除    sets = frozenset([1, 2, 3]) # 返回新的frozenset对象(集合)    num = len([1, 2, 3]) # 长度    lists = list((1, 'a')) # 转为list类型    tups = tuple([1, 2, 3]) # 转为tuple元组类型    ran = range(5) # 不可变序列    ran = range(0,5)    ran = range(0,5,2) # (起始,结束,增加量)    sets = set([1,2,3]) # 返回set集合    maps = map(lambda x, y: x*y, [1, 2, 3], [65, 66, 67, 68]) # 返回一个迭代器,元素通过自定义函数筛选,可接收多个iterable参数 => [65, 132, 201]    iters = zip(["A", "B", "C", "D", "E", "F"], [1, 2, 3]) # 创建新的迭代器, 聚合每个迭代器元素 => [('A', 1), ('B', 2), ('C', 3)]    iters = iter([1, 2, 3, 4, 5]) # 返回一个迭代器对象    elem = next(iters) # 从迭代器中获取下个元素; 实现原理见 内置函数 文章 lis 块代码(http://blog.csdn.net/rozol/article/details/70769628)    iters = reversed([1,2,3]) # 返回反向的遍历器 => [3, 2, 1]    lists = [1,2,3,4,5][slice(3)] # 切片 => [1, 2, 3]    lists = [1,2,3,4,5][slice(1,3)] # [slice(3) == slice(None, 3, None) / slice(1,3) == slice(1, 3, None) / slice(1,3,1) == slice(1, 3, 1)    lists = sorted([2,5,3,1,4]) # 排序 => [1, 2, 3, 4, 5]    lists = sorted(['a','B',';','t','D','1'], key = lambda x : ord(x), reverse = True) # key:比较键的函数, reverse是否反向遍历    strs = input("请输入数据:") # 输入数据    f = open("temp.txt", "r+") # 打开文件,详情见os文章    print("字符串%d"%123) # 打印字符 => 字符串123    print("字","符", "串", sep="-") # sep为分隔 => 字-符-串    print("字","符", "串", sep="-", end="\r\n") # end为尾部 => 字-符-串/r/n    print("字","符", "串", sep="-", end="\r\n", file=open("temp.txt","w+")) # 打印到文件class Clazz:    def __init__(self, name):        self.name = name;    @classmethod # 将函数包装成类方法    def setName_cls(cls, name):        pass    @staticmethod # 将函数包装成静态方法    def setName_sta(name):        pass    def getname(self):        return self.name    def setname(self, value):        self.name = value    def delname(self):        del self.name    # property(fget=None, fset=None, fdel=None, doc=None) # 返回一个property 属性, 实现原理见 内置函数 文章 property_my 块代码(http://blog.csdn.net/rozol/article/details/70603230)    # property 为属性方法, 有两种实现方式,详情见 类 文章的 属性方法代码块(http://blog.csdn.net/rozol/article/details/69317339)     x = property(getname, setname, delname)if __name__ == "__main__":    fun()    # property 的使用    c = Clazz("柳岩")    print(c.x) # => 柳岩    c.x = '汤唯'    print(c.getname()) # => 汤唯    del c.x