How to resolve the algorithm Selectively replace multiple instances of a character within a string step by step in the Factor programming language

Published on 12 May 2024 09:40 PM
#Factor

How to resolve the algorithm Selectively replace multiple instances of a character within a string step by step in the Factor programming language

Table of Contents

Problem Statement

This is admittedly a trivial task but I thought it would be interesting to see how succinctly (or otherwise) different languages can handle it. Given the string: "abracadabra", replace programatically:

Note that there is no replacement for the third 'a', second 'b' or first 'r'. The answer should, of course, be : "AErBcadCbFD".

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Selectively replace multiple instances of a character within a string step by step in the Factor programming language

Source code in the factor programming language

USING: assocs formatting grouping kernel random sequences ;

CONSTANT: instrs {
    CHAR: a 1 CHAR: A
    CHAR: a 2 CHAR: B
    CHAR: a 4 CHAR: C
    CHAR: a 5 CHAR: D
    CHAR: b 1 CHAR: E
    CHAR: r 2 CHAR: F
}

: counts ( seq -- assoc )
    H{ } clone swap [ 2dup swap inc-at dupd of ] zip-with nip ;

: replace-nths ( seq instrs -- seq' )
    [ counts ] dip 3 group [ f suffix 2 group ] map substitute keys ;

: test ( str -- )
    dup instrs replace-nths "" like "%s -> %s\n" printf ;


"abracadabra" test
"abracadabra" randomize test

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