python核心编程第二版习题解答及执行结果第二章-py3.4实现2.docx

第二章习题解答2-4 num = input(please input a number: )please input a number: num = int(input(please input a number: ))please input a number: 2502-5(a) i=0 while i11:print(i)i+=101...(b) i=0 fori in range(11):print(i)i+=101...2-6 num=int(input(please input a num:))please input a num:366 if num0:print(fushu)elif num0:print(zheshu)else:print(zero)zheshu2-7 s=input(enter a string:)enter a string:Field foreachchar in s:print(eachchar)Field fori in range(len(s)):print(i,s[i])0 F1 i2 e3 l4 d fori,x in enumerate(s):print(i,x)0 F1 i2 e3 l4 d2-8 r=0 fori in range(5):r+=int(input(enter a num:))print(r)enter a num:44enter a num:48enter a num:5563enter a num:555618enter a num:44662## uses sum() BIF and generator expressions print(sum(int(input(please input a num:)) for i in range(5)))please input a num:2please input a num:2please input a num:2please input a num:2please input a num:210 2-10 while True:num=int(input(please input a num:(1-100)))if num in range(101):print(corect)breakelse:print(error,try again!)please input a num:(1-100)122error,try again!please input a num:(1-100)1corect2-15 num1 = int(input(please input first number:))please input first number:12 num2 = int(input(please input 2rd number:))please input 2rd number:5 num3 = int(input(please input 3st number:))please input 3st number:55 if num1 num2:num1, num2 = num2, num1 if num1 num3:num1, num3 = num3, num1 if num1 num3:num1, num3 = num3, num1 print(num1,num2,num3)5 12 55 print(num3,num2,num1)55 12 5 makeTextFile.py#!/usr/bin/env/ pythonprint(jhjjjjj)print(DONE),附：第三四章例题执行结果及源码#例3.1#!/usr/bin/env pythonmakeTextFile.py -- create text fileimportos# get filenamewhile True:fname = input(Enter file name: ) if os.path.exists(fname):#os.path.exists()函数:确认输入的文件名是否存在print(*** ERROR: %s already exists % fname)else:break# get file content (text) linesall = []print(\nEnter lines (. by itself to quit).\n)# loop until user terminates inputwhile True:entry = input( )if entry == .:breakelse:all.append(entry)# write lines to file wi