Writing file-写入文件

-写入文件内容使用write方法，该方法在文件中写入字符串，如：

file=open('newfile.txt','w')file.write('This has been written to a file')file.close()file=open('newfile.txt','r')print file.read()file.close()

执行结果：

>>>This has been written to a file>>>

• 当一个文件以写的模式被打开时，文件中存在的内容会被删除，如：

file=open('newfile.txt','r')print 'Readin initial contents'print file.read()print 'Finished'file.close()file=open('newfile.txt','w')file.write('some new text')file.close()file=open('newfile.txt','r')print 'Reading new contents'print file.read()print 'Finished'file.close()

执行结果:

>>>>Reading initial contentssome initial textFinishedReading new conentssome new textFinished>>>

• 如果写入文件成功的话，write方法返回被写入文件内容的字节数(在python2x版本中可能不同），如：

msg='hello world!'file=open('newfile.txt','w')count=file.write(msg)print countfile.close()

执行结果：

>>>>12>>>