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python内置模块一览

Python内置模块 builtins 概览，dir(builtins) 分类梳理一览。

Built-in Functions

id#

builtins.dir

builtins.id
builtins.hash
builtins.type

builtins.isinstance
builtins.issubclass

builtins.hasattr
builtins.getattr

vars#

builtins.vars
builtins.locals
builtins.globals

argparse 解析参数 args = argparser.parse_args()，调用 print(args) 打印出来的是 Namespace：

Namespace(debug=False, logpath='logs/19.09.30.14-MBR.log', platform=1)

调用 print(vars(args)) 以字典形式打印 object.__dict__：

{'platform': 1, 'logpath': 'logs/19.09.30.14-MBR.log', 'debug': False}

types#

None#

builtins.None
builtins.Ellipsis # 省略号

bool#

builtins.bool
builtins.False
builtins.True

builtins.any # 一组值中只要有一个为 True。

  • bool(x) 传入数值 0 为 False，传入非 0 值为 True。
  • bool(x) 传入空对象 None 为 False，传入非空对象为 True。

Sequence Types#

builtins.str - Text Sequence

builtins.list # array
builtins.tuple
builtins.range

builtins.slice

Mapping Types#

builtins.dict
builtins.map

Set Types#

builtins.set
builtins.frozenset

Binary Sequence Types#

builtins.bytes
builtins.bytearray
builtins.memoryview

len & filter#

builtins.len # 对字符串、列表等序列化数据集合求取长度（size）。

builtins.reversed
builtins.filter
builtins.sorted

builtins.zip

iterate#

enumerate#

builtins.enumerate

help(enumerate) 查看相关帮助：

class enumerate(object)
 |  enumerate(iterable, start=0)
 |
 |  Return an enumerate object.
 |
 |    iterable
 |      an object supporting iteration
 |
 |  The enumerate object yields pairs containing a count (from start, which
 |  defaults to zero) and a value yielded by the iterable argument.
 |
 |  enumerate is useful for obtaining an indexed list:
 |      (0, seq[0]), (1, seq[1]), (2, seq[2]), ...

枚举列表的索引与值。

对 enumerate 返回的对象转换为list，可知其内为 (index, value) 的 tuple 数组。

>>> l = [1,2,3,4]
>>> el = enumerate(l)
>>> list(el)
[(0, 1), (1, 2), (2, 3), (3, 4)]

for 循环遍历取 tuple 二维元素值：

>>> for i,e in enumerate(l):
...     print('l[%d] = %d' % (i, e))
...
l[0] = 1
l[1] = 2
l[2] = 3
l[3] = 4

iter & next#

builtins.iter
builtins.next 

mytuple = ("apple", "banana", "cherry")
myit = iter(mytuple)

print(next(myit))
print(next(myit))
print(next(myit))
print(next(myit)) #StopIteration Exception!!!

open#

builtins.open

builtins.eval
builtins.exec

warning/error#

builtins.Warning
builtins.UserWarning

builtins.IndexError
builtins.FileExistsError
builtins.FileNotFoundError

builtins.TypeError
builtins.ValueError

Built-in Exceptions
warnings — Warning control

refs#

30段极简Python代码

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