Python string replace the values

[Rhodri James]

On 01/09/17 18:13, Ganesh Pal wrote:
>>>> "a0000" + "1"    ===> expected was a0001
> 'a00001'

Why would you expect that?  Concatenation means "joining together", so

 >>> "foo" + "bar"
'foobar'

No other mangling of either of your original strings is going to happen; 
there is no magic going on here.

What you want is most easily done using the zfill() string method to pad 
out the user's string with zeroes:

 >>> fixed_string = "a"
 >>> user_string = "1"
 >>> final_string = fixed_string + user_string.zfill(4)
'a0001'

Note you should think VERY CAREFULLY about any user input like this. 
What are you going to do the user gives you too many digits, too few 
digits, non-digits?

-- 
Rhodri James *-* Kynesim Ltd