Learning with python: Chapter2 Variables, expressions and statements

20个关键词：

and def exec if not return assert del finally import or try break elif for in pass while class else from is print yield continue except global lambda raise

[root@CentOS python]# python
Python 2.6.6 (r266:84292, Feb 21 2013, 23:54:59)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> print 4  # use print
4
>>> type("Hello world!")  # use type()
<type 'str'>
>>> type(3.2)
<type 'float'>
>>> print 1,000,000   # use , operator printmulti-variables
1 0 0
>>> Message="What's up?"  # string
>>> n=17
>>> pi=3.1415926
>>> print Message   # print string
What's up?
>>> print n
17
>>> print pi
3.1415926
>>> type(Message),type(n),type(pi)
(<type 'str'>, <type 'int'>, <type 'float'>)
>>> 1+1
2
>>> 17
17
>>> Message   # string, compare with "print string"
"What's up?"
>>> 5**2,4*3  # ** is exponent and * is multiply
(25, 12)
>>> minute=59
>>> minute/60   # round off
0

>>> minute*100/60
98
>>> 3*1**3    # ** is prior to *
3
>>> (3*1)**3
27
>>> print Message + "Ted."   # operate string
What's up?Ted.
>>> print Message*3  # print Message for 3 times
What's up?What's up?What's up?

>>> percentage=(minute*100)//60  # // is same as / as a division operator
>>> percentage
98
>>> percentage=(minute*100)/60
>>> percentage
98