python-内置函数

Posted 2021-12-02 vaon

计算长度

In [140]: a=‘hello‘

In [141]: len(a)
Out[141]: 5

取极值

In [142]: max(‘1234‘)
Out[142]: ‘4‘

In [143]: min(‘1234‘)
Out[143]: ‘1‘

枚举

可以同时遍历索引和遍历元素

In [151]: str=‘hello‘

In [152]: for i,j in enumerate(str):
   .....:     print i,j
   .....:     
0 h
1 e
2 l
3 l
4 o

比较

cmp()

In [37]: cmp(1,2)
Out[37]: -1
In [38]: cmp(2,1)
Out[38]: 1
In [39]: cmp(1,1)
Out[39]: 0

查看变量类型

type(变量名)

In [42]: a=1
In [43]: type(a)
Out[43]: int

类型转换

In [35]: a=123
In [36]: type(a)
Out[36]: int

In [37]: a=long(a)
In [38]: type(a)
Out[38]: long

In [40]: str(1)
Out[40]: ‘1‘

zip

In [153]: s1=‘123‘

In [154]: s2=‘abc‘

In [155]: s3=‘ABC‘

In [156]: zip(s1,s2,s3)
Out[156]: [(‘1‘, ‘a‘, ‘A‘), (‘2‘, ‘b‘, ‘B‘), (‘3‘, ‘c‘, ‘C‘)]