技術標籤：python3.0python

1. Python3中只有一種整型型別int
2. 內建的type()函式可以查詢變數所指的物件型別
3. 也可以使用內建的instance()函式來判斷
4. Python中的True值是1，False值是0
5. 浮點只有單精度float,沒有double雙精度

In [1]: a=100

In [2]: type(a)
Out[2]: int

In [3]: b=a

In [4]: b
Out[4]: 100

In [5]: a='abc'

In [6]: b=a

In [7]: type(b)
Out[7]: str

In [8]: f=1.23

In [9]: type
 
(f)
Out[9]: float

In [10]: f1=1.23*e9
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-10-d99753a72dde> in <module>
----> 1 f1=1.23*e9

NameError: name 'e9' is not defined

In [
 
11]: f1=1.23e9

In [12]: 3>2
Out[12]: True

In [13]: 3>5
Out[13]: False

In [14]: True and True
Out[14]: True

In [15]: True and False
Out[15]: False

In [16]: 5>3 and 3>1
Out[16]: True

In [17]: True or True
Out[17]: True

In [18]: True or False
Out[18]: True

In [19]: 5>3 or 3<1
Out[
 
19]: True

In [20]: not False
Out[20]: True

In [21]: not True
Out[21]: False

In [22]: not 1>2
Out[22]: True

In [23]: None

In [24]: a=None

In [25]: # None 是沒有申請記憶體空間

In [26]: type(a)
Out[26]: NoneType

In [27]: # python  是動態語言

In [28]: x=10

In [29]: x=x+2

In [30]: x
Out[30]: 12

In [31]: 10/3
Out[31]: 3.3333333333333335

In [32]: 9/3
Out[32]: 3.0

In [33]: 10//3
Out[33]: 3

In [34]: 10%3
Out[34]: 1

In [35]: 2**2
Out[35]: 4

In [36]: 2**3
Out[36]: 8