7-2【任務7-2】實現(xiàn)文件內容的寫入與讀取

【任務7-2】實現(xiàn)文件內容的寫入與讀取【任務描述】（1）在項目Unit07創(chuàng)建Python程序文件7-2.py。（2）使用兩種方法將圖書數(shù)據(jù)寫入當前工作文件夾的

“myBook.txt”文件中。（3）使用兩種方法從“myBook.txt”文件中

讀取全部行，并輸出?！救蝿諏嵤?．創(chuàng)建Python程序文件7-2.py在PyCharm項目“Unit07”中，新建Python程序文件“7-2.py”，同時PyCharm主窗口顯示程序文件“7-2.py”的代碼編輯窗口，在該程序文件的代碼編輯窗口也自動添加了模板內容?！救蝿諏嵤?．編寫Python程序代碼在新建文件“7-2.py”的代碼編輯窗口已有模板注釋內容下面輸入程序代碼?！救蝿諏嵤縡ieldName=["商品編碼","圖書名稱","價格"]book=["book1","book2","book3"]book1=["12528944","PPT設計從入門到精通",79.00]book2=["12563157","給Python點顏色青少年學編程",59.80]book3=["12451724","Python從入門到項目實踐（全彩版）",99.80]book4=["12550531","Python編程錦囊（全彩版）",79.80]【任務實施】defgetSize(text):iftype(text)!=str:text=str(text)lenText=len(text)#調用len函數(shù)計算字符串的字符數(shù)量

lenTextUtf8=len(text.encode('UTF-8'))#計算字符串UTF-8編碼的長度

iflenText!=lenTextUtf8:size=int(lenText-(lenTextUtf8-lenText)/2)#計算字符中半角字符的數(shù)量

returnsizeelse:return0【任務實施】defwriteFile1():objFile=open(r"D:\PycharmProject\Unit07\myBook.txt","w")objFile.write("{0:{1}^6s}".format(fieldName[0],chr(12288)))objFile.write("{0:{1}^18s}".format(fieldName[1],chr(12288)))objFile.write("{0:{1}^10s}".format(fieldName[2],chr(12288)))objFile.write("\n")【任務實施】

#使用eval方法將字符串轉換為變量名

foritemBookinbook:objFile.write("{0:{1}^10}".format(eval(itemBook)[0],chr(12288)))objFile.write("{0:{1}<20s}".format(eval(itemBook)[1],chr(12288)))objFile.write("{0:<{1}s}".format(chr(32),str(getSize(eval(itemBook)[1]))))objFile.write("{0:{1}>6.2f}".format(eval(itemBook)[2],chr(12288)))objFile.write("\n")objFile.close()【任務實施】defwriteFile2():objFile=open(r"D:\PycharmProject\Unit07\myBook.txt","a")

#使用eval方法將字符串轉換為變量名objFile.write("{0:{1}^10}".format(book4[0],chr(12288)))

objFile.write("{0:{1}<20s}".format(book4[1],chr(12288)))objFile.write("{0:<{1}s}".format(chr(32),str(getSize(book4[1]))))objFile.write("{0:{1}>6.2f}".format(book4[2],chr(12288)))objFile.write("\n")【任務實施】defreadFile1():objFile=open(r"D:\PycharmProject\Unit07\myBook.txt","r")strText=""whileTrue:str=objFile.readline()ifstr!="":strText=strText+strelse:breakprint(strText)objFile.close()【任務實施】defreadFile2():withopen(r"D:\PycharmProject\Unit07\myBook.txt","r")asobjFile:fortxtLineinobjFile.readlines():print(txtLine,end="")objFile.close()【任務實施】try:writeFile1()writeFile2()readFile1()readFile2()exceptExceptionaserror:print(error)單擊工具欄中【保存】按鈕，保存程序文件“7-2.py”。【任務實施】

3．運行