Prolog: how to convert string to integer?

问题

So as the title says - how do you convert a string into an integer? the idea is something like this:

convert(String,Integer).

examples:
convert('1',1).
convert('33',33).

I'm using swi prolog

回答1:

Use atom_number/2. E.g:

  atom_number('123', X).
  X = 123.

回答2:

Assuming you really meant a string and not an atom, use number_codes.

?- number_codes(11, "11").
true.

?- number_codes(11, Str).
Str = [49, 49].            % ASCII/UTF-8

?- number_codes(N, "11").
N = 11.

回答3:

Perhaps use of atom_codes(?Atom, ?String) and number_chars(?Number, ?CharList) would do it.

回答4:

in Visual Prolog convert:

X=toTerm(real,H).

real/integer/unsigned...

来源：https://stackoverflow.com/questions/6782007/prolog-how-to-convert-string-to-integer