>>>infile = open("1.dat","r")    #打開(kāi)一個(gè)文件對(duì)象放在infile中
>>>infile = open("1.mp3","rb")

def main():
  fname = input("enter filename:") #首先提示用戶輸入文件名
  infile = open(fname,"r")#打開(kāi)文件并賦值給文件對(duì)象變量infile
  data = infile.read()#文件的全部?jī)?nèi)容被讀入在一個(gè)長(zhǎng)字符串中并存儲(chǔ)在data變量中
  print(data)#輸出data在屏幕上
main()

#連續(xù)調(diào)用readline（）可以的到文件中連續(xù)行，readline（）返回值都以換行符結(jié)束
#輸出文件前5行：
def main():
  infile=open("file_name","r")
  for i in range(5):
    line = infile.readline()
    print(line[:1])
#利用剪切操作去掉每行讀入的分隔符，如果輸出語(yǔ)句末尾有換行符，
#輸出操作就會(huì)自動(dòng)跳到下一行，這樣輸出的文件內(nèi)容各行之間就會(huì)多出一個(gè)空行
main()

>>> outfile = open("outfile.txt","w")
#打開(kāi)一個(gè)文件并進(jìn)行文件寫(xiě)入操作，需要一個(gè)文件接受數(shù)據(jù)，如果給出的文件名不存在則會(huì)創(chuàng)建一個(gè)新文件，如果給出的文件名存在，python將原文件刪除并創(chuàng)建一個(gè)新的空文件
>>> outfile.writelines(["hello","","liyue"])
>>> outfile.close()
>>> infile = open("outfile.txt","r")
>>> infile.read()
'hello liyue'

file = open(filename,"r")
for each_line in file.readlines():#當(dāng)文件很大會(huì)占用很大內(nèi)存
              #處理一行文件內(nèi)容
file.close()

file = open (filename,"r")
for each_line in file:
           #處理一行文件內(nèi)容
file.close()

def main():
  #用戶輸入文件名
  f1 = input("輸入一個(gè)源文件：").strip()
  f2 = input("輸入一個(gè)源文件：").strip()
  #打開(kāi)文件
  infile = open(f1,"r")
  outfile = open(f2,"w")
  #copy數(shù)據(jù)
  countLines = countChars = 0
  for line in infile:
    countLines +=1
    countChars +=len(line)
    outfile.write(line)
  print(countLines,"linesand",countChars,"char copied")
  infile.close()
  outfile.close()
main()