[Tutor] Question about string

[Alan Gauld]

"Dong Li" <dongli2020 at gmail.com> wrote

> I am new to python, so what I ask may be so basic. I don't know the
> difference between
>
> s = 'a' 'b'
> and
> s = 'a'+'b'
>
> They have the same results. Thanks for relying!

I think the differencec is that the first is purely a syntax thing so
the interpreter does the work of joining the strings together before
processing the result as a single string whereas the second the
two strings are treated separately and actual string addition
(concatenation) is done which is a much more expensive
operation in terms of computer power.

The first is only possible if you have literal strings but the second
can be used for variables:

s1 = 'a'
s2 = 'b'
s = s1 s2     # doesn't work
s = s1 + s2   # works

HTH,

-- 
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld