How to replace part, of specific order, of a string?

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How to replace part, of specific order, of a string?

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#1 by (2 votes)
#2 by (1 votes)

1

I would like to know how to replace part of a string, but only part of order N.

For example, replace the second (so only) "and" with "electricity."

Entry: Electricity

Output: Electricity

Maybe it's simple, but I'm a layman on the subject ... I already tried for split and replace , I could not.

javascript string

asked by anonymous 09.06.2018 / 06:12

2 answers

How to search using regular expression in delphi 7 [duplicate] Which character types are generated by the password_hash () function?

score 2 · Answer 1

I created a function that uses indexOf to look for the string to be replaced inside the entry and a for to iterate through it and look for the correct occurrence to be replaced.

Once the part to be replaced is found in the string, the substring method can be used to assemble a new string by concatenating the part of the input that has what is before the piece to be replaced, the substitute of the piece to be replaced and then the part of the entry that has what is there after the replaced passage.

If the part to be replaced is not found, the input string is changed invalid.

Follow the function code along with the corresponding test code:

function substituir(entrada, substituindo, substituto, ordem) {
    if (ordem === 0) return entrada;
    var upEntrada = entrada.toUpperCase();
    var upSubstituindo = substituindo.toUpperCase();
    var idx = -1;
    for (var i = 0; i < ordem; i++) {
        idx = upEntrada.indexOf(upSubstituindo, idx + 1);
        if (idx === -1) return entrada;
    }
    return entrada.substring(0, idx)
            + substituto
            + entrada.substring(idx + substituindo.length);
}

var teste1 = "Eletricidade";
var saida1 = substituir(teste1, "e", "", 2);
document.write(teste1 + " - " + saida1 + "<br>");

var teste2 = "Ana, Mariana e Luciana gostam de comer banana.";
var saida2 = substituir(teste2, "ana", "mara", 3);
document.write(teste2 + " - " + saida2 + "<br>");

var teste3 = "Azul Verde Vermelho Lilás Verde Roxo";
var saida3 = substituir(teste3, "verde", "Branco", 0);
var saida4 = substituir(teste3, "verde", "Branco", 1);
var saida5 = substituir(teste3, "verde", "Branco", 2);
var saida6 = substituir(teste3, "verde", "Branco", 3);

document.write(teste3 + " - " + saida3 + "<br>");
document.write(teste3 + " - " + saida4 + "<br>");
document.write(teste3 + " - " + saida5 + "<br>");
document.write(teste3 + " - " + saida6 + "<br>");

var teste7 = "AAAAAAAAAAAAAAAAAAAA";
var saida7 = substituir(teste7, "X", "Y", 2);
var saida8 = substituir(teste7, "A", "Z", 999);
var saida9 = substituir(teste7, "A", "Z", 5);
document.write(teste7 + " - " + saida7 + "<br>");
document.write(teste7 + " - " + saida8 + "<br>");
document.write(teste7 + " - " + saida9 + "<br>");

score 1 · Answer 2

You can do this by using Regular Expression with .replace (explanations in code):

// parâmetros da função:
// t = texto
// x = texto a ser substituído
// y = novo texto
// p = posição da ocorrência
function subs(t,x,y,p){
   var c = 0;                        // contador
   var r = new RegExp(x,'gi');       // regex: busca em todo texto e não diferencia maiúscula de minúscula
   t = t.replace(r, function(m){     // faz o replace
     c++;                            // incrementa o contador
     return (c == p) ? y : m;        // retorna para a função a string substituída na posição desejada
   });                               // se não encontrar ocorrência, retorna o texto original
   return t;                         // retorna o resultado da função
}

// exemplos
console.log( subs("Eletricidade", "e", "", 2) );
console.log( subs("Eletricidade", "e", "X", 1) );
console.log( subs("Eletricidade", "e", "X", 3) );
console.log( subs("Eletricidade", "ic", "IC", 1) );
console.log( subs("Abracadabra", "Bra", "-", 2) );

Clean Code (no comments):

function subs(t,x,y,p){
   var c = 0;
   var r = new RegExp(x,'gi');
   t = t.replace(r, function(m){
     c++;
     return (c == p) ? y : m;
   });
   return t;
}

console.log( subs("Eletricidade", "e", "", 2) );
console.log( subs("Eletricidade", "e", "X", 1) );
console.log( subs("Eletricidade", "e", "X", 3) );
console.log( subs("Eletricidade", "ic", "IC", 1) );
console.log( subs("Abracadabra", "bra", "-", 2) );