What is the best way to substitute multiple characters at a specific position in JavaScript?

Question

What is the best way to substitute multiple characters at a specific position in JavaScript?

I'm struggling to figure out how to replace more than one character at a specific index in a string.

I attempted using a FOR loop, but it didn't yield the desired results.

String.prototype.replaceAt=function(index, replacement) {
    return this.substr(0, index) + replacement+ this.substr(index + replacement.length);
}
var str = "hello world";
var indices = [1, 4, 9];
for(i = 0; i < indices.length; i++) {
    str.replaceAt(indices[i], "?");
}

After the loop, the str should be "h?ll? wor?d", but it remains as "hello world"

javascript replace

Answer 1

Answer №1

Upon reviewing the replaceAt method, it becomes clear that the original string is not being modified (due to the immutability of strings). Instead, a new string is being created. To ensure the for loop effectively replaces characters in the string, consider updating it as follows:

String.prototype.replaceAt=function(index,replacement) {
    return this.substr(0, index) + replacement+ this.substr(index + replacement.length);
}

var str = "hello world";
var indices = [1, 4, 9];

for(i = 0; i < indices.length; i++) {
    str = str.replaceAt(indices[i], "?");
}

Answer 2

Upon reviewing the replaceAt method, it becomes clear that the original string is not being modified (due to the immutability of strings). Instead, a new string is being created. To ensure the for loop effectively replaces characters in the string, consider updating it as follows:

String.prototype.replaceAt=function(index,replacement) {
    return this.substr(0, index) + replacement+ this.substr(index + replacement.length);
}

var str = "hello world";
var indices = [1, 4, 9];

for(i = 0; i < indices.length; i++) {
    str = str.replaceAt(indices[i], "?");
}

Answer 3

Answer №2

Each step of the replacement process requires a specific assignment.

String.prototype.replaceAt = function(index, replacement) {
    return this.substr(0, index) + replacement + this.substr(index + replacement.length);
}

var str = "hello world";
var indices = [1, 4, 9];

for (var i = 0; i < indices.length; i++) {
    str = str.replaceAt(indices[i], "?");
}

console.log(str);

Answer 4

Each step of the replacement process requires a specific assignment.

String.prototype.replaceAt = function(index, replacement) {
    return this.substr(0, index) + replacement + this.substr(index + replacement.length);
}

var str = "hello world";
var indices = [1, 4, 9];

for (var i = 0; i < indices.length; i++) {
    str = str.replaceAt(indices[i], "?");
}

console.log(str);

What is the best way to substitute multiple characters at a specific position in JavaScript?

Answer №1

Answer №2

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