python数据类型

[root@localhost python]# ipython3
In [1]: a=1  //变量名=变量值；在堆内存中的一个区域存了一个值为1，内存分为堆内存和栈内存，栈内存的是引用。指向堆内存中的值。

In [4]: b=88

In [5]: c=a+b

In [7]: c
Out[7]: 89

In [8]: a
Out[8]: 1

In [9]: type(a)
Out[9]: int

In [10]: type(c)
Out[10]: int

In [11]: str="hello"

In [12]: str
Out[12]: ‘hello‘

In [13]: x,y=1,2

In [14]: x
Out[14]: 1

In [15]: y
Out[15]: 2

In [16]:

In [16]: type(str)
Out[16]: str

In [1]: import keyword

In [2]: keyword.kwlist
Out[2]: 
[‘False‘,
 ‘None‘,
 ‘True‘,
 ‘and‘,
 ‘as‘,
 ‘assert‘,
 ‘break‘,
 ‘class‘,
 ‘continue‘,
 ‘def‘,
 ‘del‘,
 ‘elif‘,
 ‘else‘,
 ‘except‘,
 ‘finally‘,
 ‘for‘,
 ‘from‘,
 ‘global‘,
 ‘if‘,
 ‘import‘,
 ‘in‘,
 ‘is‘,
 ‘lambda‘,
 ‘nonlocal‘,
 ‘not‘,
 ‘or‘,
 ‘pass‘,
 ‘raise‘,
 ‘return‘,
 ‘try‘,
 ‘while‘,
 ‘with‘,
 ‘yield‘]

In [3]: 

In [4]: print(‘hello‘,‘world‘,‘zyj‘,‘hello‘) //输出多个变量
hello world zyj hello

In [5]: print(111+222) //输出表达式
333

In [6]: exit
[root@localhost python]#vim 3.py  
 1 a=35
  2 print("my age is:%d"%a )  //变量替换
[root@localhost python]# python3 3.py 
my age is:35
[root@localhost python]#vim 3.py  
  1 a=35
  2 b=10
  3 print("my age is:%d"%a+b)
[root@localhost python]# python3 3.py 
Traceback (most recent call last):
  File "3.py", line 3, in <module>
    print("my age is:%d"%a+b) //错误行
TypeError: must be str, not int  //错误类型
[root@localhost python]#vim 3.py  
  1 a=35
  2 b=10
  3 print("my age is:%d"%(a+b)) //表达式需要用括号括起来
[root@localhost python]# python3 3.py 
my age is:45
[root@localhost python]#vim 3.py 
  1 a=35
  2 b=10
  3 my_name="zyj"
  4 print("my age is:%d,my name is:%s" %(a+b,my_name)) //如果需要多个变量替换也要加小括号，并且每个变量用逗号隔开，%d代表整数类型替换，%s代表所有的类型变量替换，可以只记住%s
[root@localhost python]# python3 3.py 
my age is:45,my name is:zyj

[root@localhost python]#vim 3.py 
money=2
print("I have money:%4d",%money) //输出为4位，默认位空格
[root@localhost python]# python3 3.py 
I have money:  2

[root@localhost python]#vim 3.py 
money=2
print("I have money:%04d" %money) //不够4位前面用0填充

[root@localhost python]# python3 3.py 
I have money:0002