Problem Explanation:
- You will create a program that takes a sentence, then search for a word in it and replaces it for a new one while preserving the uppercase if there is one.
Hint: 1
- Find the index where
before
is in the string.
Hint: 2
- Check first letter case.
Hint: 3
- Strings are immutable, you will need to save the edits on another variable, even if you must reuse the same one just to make it look like the changes where done using just that one variable.
Spoiler Alert!
Solution ahead!
Code Solution #1:
function myReplace(str, before, after) {
// Find index where before is on string
var index = str.indexOf(before);
// Check to see if the first letter is uppercase or not
if (str[index] === str[index].toUpperCase()) {
// Change the after word to be capitalized before we use it.
after = after.charAt(0).toUpperCase() + after.slice(1);
}
// Now replace the original str with the edited one.
str = str.replace(before, after);
return str;
}
Code Solution #2:
function myReplace(str, before, after) {
//Create a regular expression object
var re = new RegExp(before,"gi");
//Check whether the first letter is uppercase or not
if(/[A-Z]/.test(before[0])){
//Change the word to be capitalized
after = after.charAt(0).toUpperCase()+after.slice(1);
}
//Replace the original word with new one
var newStr = str.replace(re,after);
return newStr;
}
Code Solution #3:
function myReplace(str, before, after) {
// create a function that will change the casing of any number of letter in parameter "target"
// matching parameter "source"
function applyCasing(source, target) {
// split the source and target strings to array of letters
var targetArr = target.split("");
var sourceArr = source.split("");
// iterate through all the items of sourceArr and targetArr arrays till loop hits the end of shortes array
for (var i = 0; i < Math.min(targetArr.length, sourceArr.length); i++){
// find out the casing of every letter from sourceArr using regular expression
// if sourceArr[i] is upper case then convert targetArr[i] to upper case
if (/[A-Z]/.test(sourceArr[i])) {
targetArr[i] = targetArr[i].toUpperCase();
}
// if sourceArr[i] is not upper case then convert targetArr[i] to lower case
else targetArr[i] = targetArr[i].toLowerCase();
}
// join modified targetArr to string and return
return (targetArr.join(""));
}
// replace "before" with "after" with "before"-casing
return str.replace(before, applyCasing(before, after));
}
Code Explanation:
- Read comments on program.
Credits:
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