如何在instance.save（）後刪除input.txt文件的所有內容？

Question

text = "sample sample" 
text_file = open("input.txt", "r+b") 
text_file.write(text) 
instance.src_after = File(text_file) 
instance.save() 
text_file.close() 

如何刪除instance.save()之後的所有文件內容input.txt？

Answer 1

使用file.truncate：

text_file.truncate(0) 

幫助上file.truncate：

>>> print file.truncate.__doc__ 
truncate([size]) -> None. Truncate the file to at most size bytes. 

Size defaults to the current file position, as returned by tell().