python（一）内置函数和变量

内置函数

python的内置函数可以直接使用，无需import

函数主要分为以下几大类：

1. 计算

• abs() 求绝对值
• hash() 求哈希值
• bin(x) 求二进制数字
• divmod(a, b) 求商和余数
• pow(x, y[, z]) 求n次方
• round(number[, ndigits]) 控制精度

2. 循环、迭代、排序

• all()/any()/filter(function, iterable)/itertools.filterfalse() 判断、正/反过滤
• map(function, iterable, ...) 转化
• enumerate(iterable, start=0) 带序号的迭代
• zip(*iterables)/itertools.zip_longest() 多个迭代
• iter(object[, sentinel])/next(iterator[, default]) 生成迭代器
• reversed(seq) 生成逆序迭代器
• max(iterable, *[, key, default])/max(arg1, arg2, *args[, key])/min(iterable, *[, key, default])/min(arg1, arg2, *args[, key]) 求最大/最小值
• class range(stop)/class range(start, stop[, step])
• sorted(iterable, *, key=None, reverse=False)/functools.cmp_to_key() 带有key的排序（不建议使用只能用于list的原地排序方法sort()）
• sum(iterable[, start]) 求和

3. 类和对象、系统

• callable(object)
• repr(object)
• dir()
• id(object)
• input([prompt])
• issubclass(class, classinfo)
• len(s)
• isinstance(object, classinfo)/class type(object)/class type(name, bases, dict) 建议使用type()，isinstance允许子类实例属于父类
• open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)
• print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)

4. 字符串

• class float([x])
• eval(expression[, globals[, locals]])
• chr(i)/ord(c)

5. TBD

TBD:

• ascii(object)
• breakpoint(*args, **kws)
• class bytearray([source[, encoding[, errors]]])
• class bytes([source[, encoding[, errors]]])
• compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)
• class complex([real[, imag]])
• delattr(object, name)/getattr(object, name[, default])/hasattr(object, name)/setattr(object, name, value)
• class dict(**kwarg)
• exec(object[, globals[, locals]])
• format(value[, format_spec])
• class frozenset([iterable])
• globals()/locals()
• help([object])
• hex(x)
• class memoryview(obj)
• oct(x)
• class property(fget=None, fset=None, fdel=None, doc=None)
• class slice(stop)/class slice(start, stop[, step])
• @staticmethod
• class str(object='')/class str(object=b'', encoding='utf-8', errors='strict')
• super([type[, object-or-type]])
• vars([object])

内置变量

• False
• True
• None
• NotImplemented
• Ellipsis: The same as the ellipsis literal “...”. Special value used mostly in conjunction with extended slicing syntax for user-defined container data types.
• debug: This constant is true if Python was not started with an -O option. See also the assert statement.