Python上個手

? ??Python，由吉多·范羅蘇姆（Guido van Rossum）在1989打發圣誕節放假時間的一門“課余”編程項目，至今已有二十多年的歷史，語法簡潔清晰，深受喜愛；

1. 小窺
   

   # 查看版本
   python -V # 輸出
   print "hello" # 輸入
   str = raw_input("press any key")
   print str# 注釋
   print "www.cnblogs.com" # link # 幫助
   dir(list)
   help(list)

2. 變量
   

   # 無需聲明和刪除，直接賦值；type為內置函數，查詢類型；
   a = 10
   print a,type(a)
   a = “hello”
   print a,type(a)
   a += “ word”
   print a,type(a)

3. 列表、元組和詞典
   

   #####
   # 1. 列表：list，數據如同STL <list>，下標從0開始，支持添加刪除
   province = ['GuangDong', 'ZheJiang', 'HeNan', 'XinJang', 'HeiLongJiang']
   print province[2]
   province.append(‘HuBei’)
   delete province[1]# 訪問支持：[下限：上限：步長]，上限不包括在內
   print province[:3]        # idx from 0 to 7
   print province[3:]          # idx from 3 to end
   print province[0:5:2]     # from 0 to 4 with 2 steps
   print province[3:0:-1]    # from 2 to 1 with -1 steps
   print province[-1]          # the last one
   print province[-3]          # the second one from last                    #####
   # 2. 元組：Tuples，如同list，不過不能改變；如12個月英文名之類的常量
   days = ('Morning','Afternoon','Night')
   print days,type(days)# 字符串是一種triple
   str = “Hello world”
   print str[2:5]#####
   # 3. 詞典：Dictionaries， 如同hash, 元素結構為 key:value；如成績
   stu_score = {'ZhangSan':34,'LiSi':98, 'WangWu':99}# 新增key:value
   str_score['LiLei'] = 100# 刪除key
   delete str_score['ZhangSan']# 檢查    
   if str_score.has_key(‘HanMeiMei’):print “got HanMeimei ”
   else print “not find HanMeiMei”# 打印所有key，values?
   print stu_score.keys(),str_score.values()
   values = stu_score.values()
   values.sort()
   print values,length(values)

4. 循環
   

   # Python中語句后無“；”結尾；無“｛｝”，通過TAB（4個空格）
   # 1. while
   a = 0
   while (a < 10)a += a+1;print a
   # 2. if
   y = True
   if y == True:print “y is true”
   elif y == False:print “y is false”
   else:print “value of y is error.”#3. For
   tmp = [1,’a’,’sdfa’,242]
   for value in tmpprint value# 判斷符號 >, >=, <, <=, ==, !=, in

5. 函數
   

   # 定義函數show
   def show(list, info)for entry in list:print entryreturn input(info) + 1    # input輸出數字
   # 表傳指針，bulid-in傳值
   list = [1,2,3]
   info = “press num: “
   def show (list, info)list[1]=3info = “changed”
   show(list, info)
   print list,info

6. 類
   

   # 定義類
   class Shapedef __int__(self, x, y): # 構造self.x = xself.y = ydef area():print self.x * self.y
   shape = Shape(100,20)
   class Square(Shape)    # 繼承def __int__(self, x):self.x = self.y = x# 對象詞典
   class_dic = {}     
   class_dic[“Shape”] = Shape(100,20)
   class_dic[“Square”] = Square(100,20)
   print class_dic[“Shape”].area
   print class_dic[“Square”].area

7. 模塊
   

   # 模塊：只定義集（庫），比如變量、函數和類
   # 可以自定義模塊和模塊包
   import test_module
   import dir.module  # 相同類型放一個目錄

8. 文件操作
   

   Ofile = open(‘file’, ‘r’)
   Ofile.seek(45,0)
   # 支持seek、tell, readline, readlins, wirte, close

9. 異常處理

try:a = input(“press characters”)
except NameError:print “input a num”

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[Reference]

http://zh.wikipedia.org/zh-cn/Pythonhttp://www.sthurlow.com/python/http://www.cnblogs.com/vamei/archive/2012/05/28/2521650.html