import xlwtimport xlrddef read_old_data(row0_len):    try:        filename="./图书.xls"        old_data = []#读取表格已有内容        data = xlrd.open_workbook(filename)        sheet0 = data.sheet_by_index(0)        nrows = sheet0.nrows  #获取该sheet中的有效行数        print("Info:读取到已有数据表格")        print("有效行数：",nrows)        for i in range(nrows):            for j in range(row0_len):                old_data.append(sheet0.cell(i,j).value)        print("共有旧的数据：",len(old_data))    except IOError:        print("Info: 没有找到文件或读取文件失败/n1 =>新建图书.xls文件")        nrows=0    return old_data,nrowsdef new_book():    book = []    print_value=("书名","作者","编号","位置","数量")    row0_len=len(print_value)#列数    input_value=''    '''    try:    '''    (old_data,nrows)=read_old_data(row0_len)        #打开存储    book_excel = xlwt.Workbook()    sheet1 = book_excel.add_sheet("books",cell_overwrite_ok=0)    #写入旧数据：    for i in range(nrows):        for j in range(row0_len):            sheet1.write(i,j,old_data[(i*row0_len)+j])    while(1):        print("添加新书")        #输入        for i in range(row0_len):            print("请输入："+print_value[i])            input_value = input()            #判断是否输出            if(input_value == 'q'):                book_excel.save("图书.xls")                return            book.append(input_value)        #保存到硬盘        for i in range(row0_len):            sheet1.write(nrows,i,book[i])        nrows=nrows+1        book=[]#清空book缓存    returndef search():    #打开excel    book_excel = xlrd.open_workbook("图书.xls")    sheet1 = book_excel.sheets()[0]    book_num =sheet1.nrows    #while(1):    #输入书名    bookname = input("请输入书名：")    find_flag=0    #查找    for i in range(book_num):        if(bookname == sheet1.cell_value(i,0)):            if(int(sheet1.cell_value(i,4))>0):                find_flag=1                print("书名：",sheet1.cell_value(i,0))                print("作者：",sheet1.cell_value(i,1))                print("位置：",sheet1.cell_value(i,3))                print("库存（本）：",sheet1.cell_value(i,4))                return    if(find_flag==1):        print("查无此书。")    returndef borrow():    #打开excel    book_excel =xlrd.open_workbook("图书.xls")    sheet1 = book_excel.sheets()[0]    book_num = sheet1.nrows    row0_len=5#5列    while(1):        #输入书名        bookname = input("请输入书名：")        if(bookname == 'q'):            return        #查找        for i in range(0,book_num):            if(bookname == sheet1.cell(i,0).value):                kucun=int(sheet1.cell_value(i,4))                                if(kucun>0):                    (old_data,nrows)=read_old_data(row0_len)#5列                    book_excel_w = xlwt.Workbook("图书.xls")                    sheet2 = book_excel_w.add_sheet("books",cell_overwrite_ok=True)                    #写入旧数据：                    for n in range(nrows):                        for j in range(row0_len):                            sheet2.write(n,j,old_data[(n*row0_len)+j])                                        print("借到了！")                    sheet2.write(i,4,str(kucun-1))                    print("剩余库存：",kucun-1)                    book_excel_w.save("图书.xls")                    break    returndef main_window():    while(1):        print("/n====图书管理系统====")        print("1.新书加入")        print("2.书籍查询")        print("3.图书借阅")        print("========4退出=======")        x= (input("请输入你的操作"))        print('/n')        if(x == '1'):            new_book()        elif(x=='2'):            search()        elif(x=='3'):            borrow()                    elif(x=='4'):            break        else:            print("输入无效")    returnmain_window()