python核心編程第二版習(xí)題解答及執(zhí)行結(jié)果第二章-py3.4實(shí)現(xiàn)

1、第二章習(xí)題解答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 i<11:print(i)i+=101.(b)>>> i=0>>> for i in range(11):

2、print(i)i+=101.2-6>>> num=int(input("please input a num:")please input a num:366>>> if num<0:print('fushu')elif num>0:print('zheshu')else:print('zero')zheshu2-7>>> s=input('enter a string:')enter a string:Field>>> fo

3、r eachchar in s:print(eachchar)Field>>> for i in range(len(s):print(i,si)0 F1 i2 e3 l4 d>>> for i,x in enumerate(s):print(i,x)0 F1 i2 e3 l4 d2-8>>> r=0>>> for i in range(5):r+=int(input('enter a num:')print(r)enter a num:44enter a num:48enter a num:5563ent

4、er 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:nu

5、m=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 inpu

6、t 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 =

7、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：第三四章例題執(zhí)行結(jié)果及源碼#例3.1#!/usr/bin/env python'makeTextFile

8、.py - create text file'import os# get filenamewhile True: fname = input('Enter file name: ') if os.path.exists(fname):#os.path.exists()函數(shù):確認(rèn)輸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

9、('.' by itself to quit).n")# loop until user terminates inputwhile True: entry = input('> ') if entry = '.': break else: all.append(entry)# write lines to file with NEWLINE line terminatorfobj = open(fname, 'w') #打開文件準(zhǔn)備進(jìn)行寫操作fobj.write('n'.join(all) #將內(nèi)

10、存中內(nèi)容逐行寫入文件fobj.close() #print( 'DONE!') '''#例3.2#!/usr/bin/env python'readTextFile.py - read and display text file'# get filenamefname = input('Enter file name: ')print()# attempt to open file for readingtry: fobj = open(fname, 'r')except IOError as e: #py

11、3修改，舊版本為except IOError, e: print("* file open error:", e)else: # display contents to the screen for eachLine in fobj: print( eachLine), fobj.close()#例4.1 def displayNumType(num): print(num, 'is',) if isinstance(num, (int, float, complex):#isinstance()判斷對(duì)象類型 print('a number of type:', type(num)._name_) else: print('not a number at all!')displayNumType(-69)displayNumType(9999999999