String manipulation in prolog
prolog
Solution
A string it's a list of char codes, while an atom it's, well, atomic, i.e. indivisible, but there is sub_atom/5 to access parts of the atomic data.
Here some string example:
1 ?- L = "ABCDEF".
L = [65, 66, 67, 68, 69, 70].
2 ?- L = "ABCDEF", maplist(succ, L, N), format('~s', [N]).
BCDEFG
L = [65, 66, 67, 68, 69, 70],
N = [66, 67, 68, 69, 70, 71].
3 ?- L = "ABCDEF", maplist(succ, L, N), format('~s', [N]), atom_codes(A, N).
BCDEFG
L = [65, 66, 67, 68, 69, 70],
N = [66, 67, 68, 69, 70, 71],
A = 'BCDEFG'.
If the analysis and transformation require detail then usually it's better to use DCGs
Problem
Premise So I'm trying to break up a given String into a list of characters, these characters will then be edited/changed and reassigned into the list after which the list will be reconstructed back into a String. An example: Given `String : "ABCDEFG"` Character `list : [A,B,C,D,E,F,G]` Operation changes the list to something like the following: [E,F,G,H,I,J,K] (Or something similar). And then gets reconstructed into a String: ``` "EFGHIJK" ``` Question I am looking for a way to access individual elements inside of a String. If it were Java I would use a command like `charAt(int i)` but I don't know if such a command exists within prolog. Note I am a new `prolog` programmer so I'm not familiar with most `prolog` operations. Thanks for your time.