Python学习入门经典实例.docVIP

#* 1 你好 #打开新窗口,输入:#!?/usr/bin/python#?-*-?coding:?utf8?-*-?s1=input(Input?your?name:)print(你好,%s?%?s1)知识点:????*?input(某字符串)函数:显示某字符串,并等待用户输入.????*?print()函数:如何打印.????*?如何应用中文??? *?如何用多行注释???? 2 字符串和数字 但有趣的是,在javascript里我们会理想当然的将字符串和数字连接,因为是动态语言嘛.但在Python里有点诡异,如下: #!?/usr/bin/pythona=2b=testc=a+b 运行这行程序会出错,提示你字符串和数字不能连接,于是只好用内置函数进行转换 #!?/usr/bin/python#运行这行程序会出错,提示你字符串和数字不能连接,于是只好用内置函数进行转换a=2b=testc=str(a)+bd=1111e=a+int(d)#How?to?print?multiply?valuesprint?(c?is?%s,e?is?%i?%?(c,e))知识点:????*?用int和str函数将字符串和数字进行转换????*?打印以#开头,而不是习惯的//????*?打印多个参数的方式???? 3 列表 #!?/usr/bin/python#?-*-?coding:?utf8?-*-#列表类似Javascript的数组,方便易用#定义元组word=[a,b,c,d,e,f,g]#如何通过索引访问元组里的元素a=word[2]print?(a?is:?+a)b=word[1:3]print?(b?is:?)print?(b)?#?index?1?and?2?elements?of?word.c=word[:2]print?(c?is:?)print?(c)?#?index?0?and?1?elements?of?word.d=word[0:]print?(d?is:?)print?(d)?#?All?elements?of?word.#元组可以合并e=word[:2]+word[2:]print?(e?is:?)print?(e)?#?All?elements?of?word.f=word[-1]print?(f?is:?)print?(f)?#?The?last?elements?of?word.g=word[-4:-2]print?(g?is:?)print?(g)?#?index?3?and?4?elements?of?word.h=word[-2:]print?(h?is:?)print?(h)?#?The?last?two?elements.i=word[:-2]print?(i?is:?)print?(i)?#?Everything?except?the?last?two?charactersl=len(word)print?(Length?of?word?is:?+?str(l))print?(Adds?new?element)word.append(h)print?(word)#删除元素del?word[0]print?(word)del?word[1:3]print?(word)知识点:????*?列表长度是动态的,可任意添加删除元素.????*?用索引可以很方便访问元素,甚至返回一个子列表????*?更多方法请参考Python的文档 4 字典 #!?/usr/bin/pythonx={a:aaa,b:bbb,c:12}print?(x[a])print?(x[b])print?(x[c])for?key?in?x:????print?(Key?is?%s?and?value?is?%s?%?(key,x[key]))????知识点:????*?将他当Java的Map来用即可. 5 字符串 比起C/C++,Python处理字符串的方式实在太让人感动了.把字符串当列表来用吧. #!?/usr/bin/pythonword=abcdefga=word[2]print?(a?is:?+a)b=word[1:3]print?(b?is:?+b)?#?index?1?and?2?elements?of?word.c=word[:2]print?(c?is:?+c)?#?index?0?and?1?elements?of?word.d=word[0:]print?(d?is:?+d)?#?A