python2 与 pyhton3的输入语句写法小结

>>> a = input()
>>> type(a)
<type 'int'>
>>> a
>>> a = input()
1.23
>>> type(a)
<type 'float'>
>>> a
1.23

>>> r = input()
hello

Traceback (most recent call last):
 File "<pyshell#50>", line 1, in <module>
 r = input()
 File "<string>", line 1, in <module>
NameError: name 'hello' is not defined

>>> r = input()
'hello'
>>> r
'hello'
>>> r = input()
"hello"
>>> r
'hello'

>>> name = input('please input name：')
please input name：'Tom'
>>> print 'Your name : ',name
Your name : Tom

>>> a = raw_input()
>>> type(a)
<type 'str'>
>>> a
'1'
>>> a = raw_input()
'hello'
>>> type(a)
<type 'str'>
>>> a
"'hello'"

>>> a = int(raw_input())
>>> type(a)
<type 'int'>
>>> a
>>> a = float(raw_input())
1.23
>>> type(a)
<type 'float'>
>>> a
1.23

>>> a, b = map(int, raw_input().split())
20
>>> a
>>> b
>>> l = list(map(int, raw_input().split()))
2 3 4
>>> l
[1, 2, 3, 4]

>>> help(input)
Help on built-in function input in module __builtin__:

input(...)
 input([prompt]) -> value
 
 Equivalent to eval(raw_input(prompt)).

>>> help(eval)
Help on built-in function eval in module __builtin__:

eval(...)
 eval(source[, globals[, locals]]) -> value
 
 Evaluate the source in the context of globals and locals.
 The source may be a string representing a Python expression
 or a code object as returned by compile().
 The globals must be a dictionary and locals can be any mapping,
 defaulting to the current globals and locals.
 If only globals is given, locals defaults to it.

可以把list,tuple,dict和string相互转化。
#################################################
字符串转换成列表
>>>a = "[[1,2], [3,4], [5,6], [7,8], [9,0]]"
>>>type(a)
<type 'str'>
>>> b = eval(a)
>>> print b
[[1, 2], [3, 4], [5, 6], [7, 8], [9, 0]]
>>> type(b)
<type 'list'>
#################################################
字符串转换成字典
>>> a = "{1: 'a', 2: 'b'}"
>>> type(a)
<type 'str'>
>>> b = eval(a)
>>> print b
{1: 'a', 2: 'b'}
>>> type(b)
<type 'dict'>
#################################################
字符串转换成元组
>>> a = "([1,2], [3,4], [5,6], [7,8], (9,0))"
>>> type(a)
<type 'str'>
>>> b = eval(a)
>>> print b
([1, 2], [3, 4], [5, 6], [7, 8], (9, 0))
>>> type(b)
<type 'tuple'>

>>> a = input()
10
>>> type(a)
<class 'str'>
>>> a
'10'