用数组中的元素替换字符“*”的实例 - JavaScript

Question

I know that I'm going to need a blank, empty array, and push characters from the sentence into the array if they aren't asterisks.

I think this will help me understand what to do once I actually want to iterate through the items in the array and use them as the replacements.

function replaceAsterisk(sentence, newWords) {

  let newArray = [];

  let character = sentence.split("");

  console.log(character);

  // if the character is not an asterisk, push it into the new array
  if (character !== "*") {
    newArray.push(character);
  }

  // if the character is an asterisk, push "cat" into the new array
  else {
    newArray.push("cat");
  }
  // return new array as a string
  return newArray.join(" ");
}

console.log(replaceAsterisk("My name is * and I am a *.", ["Sabrina", "Black Cat", "extra", "words"]));

Even now, this is not pushing "cat" into the array - why?

Answer 1

Use String.replace() with a function that generates the replacement string. In the function get the current replacement from newWords using a counter:

 function replaceAsterisk(sentence, newWords) { let counter = 0; return sentence.replace(/\\*/g, () => newWords[counter++] || ''); } console.log(replaceAsterisk("My name is * and I am a *.", ["Sabrina", "Black Cat", "extra", "words"])); 

Answer 2

You have to loop through all the characters first, see below the example.

 function replaceAsterisk(sentence, newWords) { let newArray = []; let character = sentence.split(""); console.log(character); character.forEach(function(c){ // if the character is not an asterisk, push it into the new array if (c !== "*") { newArray.push(c); } // if the character is an asterisk, push "cat" into the new array else { newArray.push("cat"); } }); // return new array as a string return newArray.join(""); } console.log(replaceAsterisk("My name is * and I am a *.", ["Sabrina", "Black Cat", "extra", "words"])); 

Answer 3

You need to loop through all of the characters in the sentence:

 function replaceAsterisk(sentence, newWords) { let newArray = []; for( let i = 0; i < sentence.length; i++) { // This line character = sentence[i]; // if the character is not an asterisk, push it into the new array if (character !== "*") { newArray.push(character); } // if the character is an asterisk, push "cat" into the new array else { newArray.push("cat"); } } // return new array as a string return newArray.join(" "); } console.log(replaceAsterisk("My name is * and I am a *.", ["Sabrina", "Black Cat", "extra", "words"])); 

Answer 4

This works. Splitting on empty strings can be weird (See MDN...split )

  let newArray = [], sentence = "My name is * and I am a *."; for (let char of sentence){ newArray.push(char); } for(let i = 0; i < newArray.length; i++){ if(newArray[i] == "*"){ newArray[i] = "cat"; } } console.log(newArray); 

Answer 5

you can use regex group match and Array.prototype.shift

 replaceAsterisk = (text, words) => { const _words = words.slice(); return text.replace(/(\\*)/g, (match) => _words.shift() || match); } // valid input const output1 = replaceAsterisk("My name is * and I am a *.", ["Sabrina", "Black Cat", "extra", "words"]); console.log(output1); // empty input const output2 = replaceAsterisk("My name is * and I am a *.", []); console.log(output2); 

Answer 6

You need to loop through each of the characters in the sentence, and get the word to replace with using shift :

 function replaceAsterisk(sentence, newWords) { let newStr = ""; [...sentence].forEach(char => { if (char != "*") { newStr += char; } else { newStr += newWords.shift(); } }); return newStr; } console.log(replaceAsterisk("My name is * and I am a *.", ["Sabrina", "Black Cat", "extra", "words"])); 

Answer 7

How would you do this if you had to loop around the array? So for instance, if you had

replaceAsterisk('Marching is fun: *, *, *, ,', ['left'; 'right']): // => 'Marching is fun, left, right, left, right!' /