【测试开发】python系列教程：Python数据类型转换

>>> a='1'
>>> int(a)
1
#如果转化后的类型不符合，报错
>>> b='a'
>>> int(b)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: 'a'

>>> a=1
>>> float(a)
1.0
#如果不能转
>>> b='a'
>>> float(b)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: could not convert string to float: 'a'

>>> complex(a)
(1+0j)
>>> complex(1)
(1+0j)
>>> complex(2)
(2+0j)
>>> complex(3.2)
(3.2+0j)

>>> a=1
>>> str(a)
'1'
>>> b=float('1')
>>> str(b)
'1.0'

>>> s='aa'
>>> repr(s)
"'aa'"

>>> repr(s)
"'aa'"
>>> str(s)
'aa'

>>> a=7
>>> eval('a*7')
49
>>> eval('2+2')
4
>>> eval('{"a":1}')
{'a': 1}

>>> clistone=['1']
>>> tuple(clistone)
('1',)

>>> a=(1,)
>>> list(a)
[1]

>>> a=set('rooe')
>>> a
{'o', 'e', 'r'}
#重复的会被删除
>>> b='123221'
>>> set(b)
{'2', '3', '1'}

>>> dict() #创建空的
{}
>>> dict(a=1)# 传入关键字
{'a': 1}
>>> dict(zip(['one'],[1])) # 映射函数方式来构造字典
{'one': 1}

>>> a = frozenset(range(10))
>>> a
frozenset({0, 1, 2, 3, 4, 5, 6, 7, 8, 9})

>>> chr(0*30)
'\x00'

>>> ord('a')
97
>>> ord('b')
98

>>> hex(1)
'0x1'

>>> oct(1)
'0o1'