[Tutor] question on string

[Kent Johnson]

Gilbert Tsang wrote:
> Hi there,
> 
> I would like to construct some string objects using the cprintf-style 
> format:
> 
> command_string = "diff -u %s %s > %s.patch" % ( src, dst, file )
> 
> Of course it is illegal in python but I couldn't figure out a way to 
> construct strings with that kind of formatting and substitution.

Actually that is correct as written! (though 'file' is a poor choice of variable name as it shadows the built-in file() function...)

 >>> src = 'mySource'
 >>> dst = 'myNewSource'
 >>> file = 'diff.out'
 >>> command_string = "diff -u %s %s > %s.patch" % ( src, dst, file )
 >>> command_string
'diff -u mySource myNewSource > diff.out.patch'

See http://docs.python.org/lib/typesseq-strings.html for details on string formatting.

Kent