馮唐--python學習日記(5)

例程：

>>> import random
>>> import sys
>>> SecretNumber= random.randint(1,100)
>>> print "i'm thinking of a number between 1 to 100"
i'm thinking of a number between 1 to 100
>>> while(1):
 print "Guess my number."
 NumberGuess = int(sys.stdin.readline())
 if (NumberGuess == SecretNumber):
  print "Correct! Choosing a new number..."
  SecretNumber = random.randint(1,100)
 elif (NumberGuess > SecretNumber):
  print "lower."
 else:
  print "Eigher."

Guess my number.
9
Eigher.
Guess my number.
5
Eigher.
Guess my number.
99
lower.
Guess my number.
56
Eigher.
Guess my number.
77
Eigher.
Guess my number.
88
Eigher.
Guess my number.
95
lower.
Guess my number.
90
Correct! Choosing a new number...
Guess my number.
90
Eigher.
Guess my number.
95
lower.
Guess my number.
95
lower.
Guess my number.
93
lower.
Guess my number.
91
Correct! Choosing a new number...
Guess my number.
92
lower.
Guess my number.
80
Eigher.
Guess my number.
86
lower.
Guess my number.
5
Eigher.
Guess my number.
85
Correct! Choosing a new number...
Guess my number.

一、if語句

if (condition):

       expression

else:

       expression

二、while語句

while (expression):

          if (condition):

                     expression

          elif:

                     expression

          ...

          else:

                    expression

 三、for循環

for in :

      (loop body)

 例

>>> import string
>>> def Encode(MessageString):
 EncodeList = []
 for Char in MessageString:
  EncodeList.append("%x" % ord(Char))
 return EncodeList

>>> def Decode(SecretMessage):
 DecodedList = []
 for hexvalue in SecretMessage:
  DecodedList.append(chr(int(hexvalue,16)))
 return string.join(DecodedList,"")

>>> if (__name__=="__main__"):
 SecretMessage = Encode("remember to drink your Ovaltine!")
 print SecretMessage
 print Decode(SecretMessage)

['72', '65', '6d', '65', '6d', '62', '65', '72', '20', '74', '6f', '20', '64', '72', '69', '6e', '6b', '20', '79', '6f', '75', '72', '20', '4f', '76', '61', '6c', '74', '69', '6e', '65', '21']
remember to drink your Ovaltine!
>>>

中斷和繼續

continue和break

例打印0～99之間的偶數，循環一次，刪除沒有處理的序列的第一個數據，打印第二個元素。

>>> MyRange = range(100)
>>> for x in MyRange:
 print x
 del MyRange[0]

錯誤處理機制

try塊和finally塊

try塊捕捉錯誤

finally是放置必須執行的代碼塊

四、利用斷言進行調試

原文轉自：http://www.kjueaiud.com