python周报第一周

首次写博客，勿喷！以后无特殊声明都是在python3.5下操作。

1.python2和python3最基础的差异

1.print

python2和python3在新手看来最大的差别无异乎是print了，我分别演示下：

liukai@bogon:~$ python -V
Python 2.7.10
liukai@bogon:~$ python
Python 2.7.10 (default, Jul 14 2015, 19:46:27)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> a="haha"
>>> print a

haha

>>> print(a)
haha

===========================================

liukai@bogon:~$ python3 -V
Python 3.5.1
liukai@bogon:~$ python3
Python 3.5.1 (default, Jan 8 2016, 23:14:28)
[GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.72)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> a="haha"
>>> print(a)
haha
>>> print a
File "<stdin>", line 1
print a
^
SyntaxError: Missing parentheses in call to 'print'

总结：python3只支持print(),python2都支持。

2.input

root@lktest:~# python -V
Python 2.7.11
root@lktest:~# python
Python 2.7.11 (default, Jan 20 2016, 11:58:42)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-16)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> a=raw_input("input your number: ")
input your number: hello
>>> a
'hello'
>>> b=input("input your number: ")
input your number: hello
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<string>", line 1, in <module>
NameError: name 'hello' is not defined

================================================

root@lktest:~# python3
Python 3.5.1 (default, Jan 3 2016, 03:35:05)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> a=raw_input("input your number: ")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'raw_input' is not defined
>>> a=input("input your number: ")
input your number: hello
>>> a
'hello'

总结：用户输入函数，python2用raw_input()，python3用input()

2.python基础知识

1.数据类型

1.整型

root@lktest:~# python3
Python 3.5.1 (default, Jan 3 2016, 03:35:05)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> a=100
>>> a=-10
>>> a=0

2.浮点型

>>> b=1.23
>>> b=-1.1
>>> b=12.3e8

3.字符串

>>> c="hello"
>>> c="My God"
>>> c="abc 123"

4.布尔值

>>> d=True
>>> d=False
>>> 6>5
True
>>> 1>4
False

5.空值

空值用None表示，但是None  !=  0

6.变量

>>> e="hello"
>>> f=10
>>> print(e,f)
hello 10

未完待续...