why it append one more letter after decode?

[Ho Yeung Lee]

it seems that it read csv file
from "\\" to "\\\\"

On Monday, October 30, 2017 at 11:03:57 AM UTC+8, Ho Yeung Lee wrote:
> i discover when 
> it 
> decode("\\",1,2)
> in interactive console
> is [
> 
> but decode in big project
> it see as
> decode(r"\\",1,2)
> [[
> 
> it double
> 
> On Monday, October 30, 2017 at 9:51:01 AM UTC+8, Ho Yeung Lee wrote:
> > if run these function to decode in python interactive console,
> > it can decode correct, 
> > 
> > but when run with a big project, it append a letter Y
> > 
> > 
> > On Monday, October 30, 2017 at 9:48:36 AM UTC+8, Ho Yeung Lee wrote:
> > > def leftrotate(l, n):
> > >     return l[n:] + l[:n]
> > > 
> > > def rightrotate(l, n):
> > >     return l[-n:] + l[:-n]
> > > 
> > > def encode(s, k, kk):
> > >     l = [ord(i) for i in s]
> > >     return leftrotate(''.join([chr(i + k) for i in l]), kk)
> > > 
> > > def decode(s, k, kk):
> > >     l = [ord(i) for i in rightrotate(s, kk)]
> > >     return ''.join([chr(i - k) for i in l])
> > > 
> > > 
> > > yesterday i add above code and run it with batch file 
> > > it can decode a correct password
> > > 
> > > then i install cx_freeze to produce executable file
> > > 
> > > but today when i run it, i see the source of encrypted password is correct
> > > but the decode one, it append one more letter Y at the end of string
> > > 
> > > why?
> > > is cx_freeze change the source python 2.7?