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get_string_code(+Index, +String, -Code)

Succeeds if Code is the value of the Index'th character code in String
Index
Integer between 1 and the length of String
String
String
Code
Variable or Integer

Description

This predicate extracts the Index'th character code from the given string String. Character codes in the string are numbered from 1 (analogous to array indices in subscript/3 and arg/3).

Note that (like all predicates that return a number as their last argument), this predicate can be used as a function inside arithmetic expressions.

Modes and Determinism

Exceptions

(5) type error
Index is not an integer
(5) type error
String is not a string
(5) type error
Code is instantiated but not to an integer
(6) out of range
Index is an integer less than 1 or greater than String's length
(4) instantiation fault
Either Index or String are uninstantated

Examples

   get_string_code(1, "abc", 97).     % succeeds
   get_string_code(3, "abc", C).      % gives C = 99

   get_string_code(2, "abc", 100).    % fails

   get_string_code(_, "abc", C).      % Error 4
   get_string_code(1, _, C).          % Error 4
   get_string_code(1.5, "abc", C).    % Error 5
   get_string_code(1, abc, C).        % Error 5
   get_string_code(0, "abc", C).      % Error 6
   get_string_code(4, "abc", C).      % Error 6

See Also

string_code / 3, string_codes / 2, string_list / 2, char_code / 2