io - Python Open a txt file without clearing everything in it?

Question

file = io.open('spam.txt', 'w')
file.write(u'Spam and eggs!
')
file.close()

....(Somewhere else in the code)

file = io.open('spam.txt', 'w')
file.write(u'Spam and eggs!
')
file.close()

I was wondering how I can keep a log.txt file that I can write to? I want to be able to open a txt file, write to it, then be able to open it later and have the contents of the previous write still be there.

Answer 1

Change 'w' to 'a', for append mode. But you really ought to just keep the file open and write to it when you need it. If you are repeating yourself, use the logging module.