2-1

>>> name = 'my name is ahwho ?'
>>> name
'my name is ahwho ?'
>>> print name
my name is ahwho ?

• name 输出的是 该对象的字符串表示形式
• print name 输出的是 name 的字符串的值

• 以name形式输出是为了非字符串也可以以字符串形式输出

>>> print '%s%s' % ('adc',123)
adc123
>>> print '%s+%s' % ('adc',123)
adc+123
>>> print '%s+%s' % ('adc',123*4)
adc+492
>>> print '%s+%s' % ('adc','123'*4)
adc+123123123123

2-2

• a) 做数字运算
• b) 输出结果 9
• c) 没有输出结果
• d) 单独执行，没有输出结果，交互解释器中输出结果为9
• e) 如果想在程序中输出9，需要有输出语句print

2-3

>>> u = 12
>>> i = 2.6534
>>> u - i
9.3466
>>> u + i
14.6534
>>> u * i
31.8408
>>> u / i
4.522499434687571
>>> u % i
1.3864
>>> u ** i
730.2970027975604

<b><i>注意: u % i 结果也是浮点数</i></b>

2-4

__author__ = 'Yuriy'
name = raw_input('what\'s your name ?\nplease input:>>>')
print 'my name is %s' % name

results:
  what's your name ?
  please input:>>>black
  my name is black

name = raw_input('please input a number')
print 'the num is %d' % int(name)
print type(int(name))

results:
please input a number24
the num is 24
<type 'int'>

2-5

n = 0
while(n<=10):   
     print n,   n += 1

0 1 2 3 4 5 6 7 8 9 10

num = [ x for x in range(11)]
i = 0
for i in num:
   print num[i],
   i += 1

0 1 2 3 4 5 6 7 8 9 10

2-6

num = int(raw_input("please input a num:\n"))
if num > 0:
   print 'positive num'
elif num < 0:
   print 'negative num'
else:
   print 'the num is 0'

2-7

myStr = raw_input("please input a num:\n")
i = 0
while i< len(myStr):
   print myStr[i],
   i += 1

please input a num:
it's my tiem
i t ' s   m y   t i e m

myStr = raw_input("please input a num:\n")
i = 0
for i in range(len(myStr)):
   print myStr[i],
   i += 1

please input a num:
it's my time to do something
i t ' s   m y   t i m e   t o   d o   s o m e t h i n g

2-8

li = []
while True:
   ch = raw_input(">>>")
   if ch == 'end':
      break
   elif ch == 'help':
      print 'Enter \'end\' to finish the input'
   elif ch.isdigit():
      li.append(ch)
   else:
      print 'Please input numbers!'
print li
i = 0
values = 0
for i in range(len(li)):
   values += int(li[i])
   i += 1
print values

>>>adc
Please input numbers!
>>>21
>>>34
>>>22
>>>12356
>>>bda
Please input numbers!
>>>BAT
Please input numbers!
>>>END
Please input numbers!
>>>end
['21', '34', '22', '12356']
12433

__author__ = 'Yuriy'
# -*- coding : utf-8 -*-
li = []while True:
   ch = raw_input(">>>")
   if ch == 'end':
      break
   elif ch == 'help':
      print 'Enter \'end\' to finish the input'
   elif ch.isdigit():
      li.append(ch)
   else:
      print 'Please input numbers!'
print li
i = 0
values = 0
while i < len(li):
   values += int(li[i]) 
  i += 1print values,

>>>20
>>>18
>>>21
>>>df
Please input numbers!
>>>end
['20', '18', '21']
59