Python 文件的读写操作：

#!/usr/bin/python
#Filename:using_file.py

poem='python'

f=file('C:\\poem.txt','w') # open for 'w'riting.It will create new file
f.write(poem)#write text to file
f.close()#close the file

f=file('C:\\poem.txt','a') # open for 'a' .It will add string at old file
f.write(' very funning')
f.close()

f=file('C:\\poem.txt')
#if no mode is specified,'r'ead mode is assumed by default
while True:
    line=f.readline()
    if len(line)==0:
        break
    print line
f.close()#close the file

不管C盘存不存在，都创建poem.txt文本，写入一些文字后。再以追加的方式打开（不是重新创建），加入文字。最后以只读的方式读取文件