Python Series two data types

1.1 Data types in Python

Python uses the object model to store data, each data type has a built-in class, and each new data is actually initialized to generate an object, with all the data being objects;

Object Three Special:

1. Identity: Memory address, can be obtained by ID ()

2. Type: Determines what type of value the object can hold, what action it can take, what rules to follow, and which can be obtained with type ()

3. Value: Real data saved by the object

1.2 Digital 1.2.1 int (integer)

1.在32位机器上，整数的位数为32位，取值范围为-2**31～2**31-1，即-2147483648～2147483647

2, on 64-bit systems, the number of integers is 64 bits, the value range is -2**63~2**63-1, that is -9223372036854775808~9223372036854775807

>>> 1010         ---------> Default decimal >>> oct (Ten) ' 012 '      ---------> Octal represents an Integer, the value preceded by a prefix "0" > >> hex ' 0xa '      ---------> hexadecimal denotes integer, prefix 0X or 0x before the number

The difference between python2.* and python3.* about integral type

python2.*
On a 32-bit machine, the number of integers is 32 bits and the value range is -2**31~2**31-1, which is -2147483648~2147483647

On a 64-bit system, the number of integers is 64 bits and the value range is -2**63~2**63-1, which is -9223372036854775808~9223372036854775807
python3.* Plastic Length Unlimited

Integer factory function int ()

1.2.2 Long (L-integer)

1.跟C语言不同，Python的长整数没有指定位宽，

2.即：Python没有限制长整数数值的大小，但实际上由于机器内存有限，我们使用的长整数数值不可能无限大。

3.注意，自从Python2.2起，如果整数发生溢出，Python会自动将整数数据转换为长整数，所以如今在长整数数据后面不加字母L也不会导致严重后果了。

1.2.3 Float (float type)

1.浮点数用来处理实数，即带有小数的数字。

2.浮点表示的形式是小数，但小数不一定都是浮点型,23和52.3E-4是浮点数的例子。E标记表示10的幂。在这里，52.3E-4表示52.3 * 10-4。

1.2.4 Complex (plural)

1.复数由实数部分和虚数部分组成，一般形式为x＋yj，其中的x是复数的实数部分，y是复数的虚数部分，这里的x和y都是实数。

注：Python中存在小数字池：-5 ～ 257

1.2.5 Boolean value

Python 3.5.1 (v3.5.1:37a07cee5969, Dec 6, 01:54:25) [MSC v.1900-bit (AM
D64)] on Win32
Type "Help", "copyright", "credits" or "license" for more information.
>>> A = 0
>>> if A:print ("a")
...
>>> A = 1
>>> if A:print ("a")
...
A
>>>

1.2.6 number-related built-in functions

1.3 string

Python Series two data types