CODEWITHSUNDEEP
javascript
Ryan
Ryan

Reputation: 3

Process a string into words seperated with the use of array

Hi so I have a question in Javascript, is it possible to use the given array such as 

["old", "great", "other", "long", "good", "last"]

and if you have a 

var str = "oldgreatotherlonggoodlastfirstnewownlittle"

and print it with spaces using the array and regex?

eg. 

old great other long good lastfirstnewownlittle

I'm just doing a simple web app in javascript just for practices.

Upvotes: 0

Views: 53

Answers (3)

Shidersz
Shidersz

Reputation: 17190

You can use Array.join() on the array to generate a regular expression, and then use this one with String.replace(). In the next example I use the replacement function of replace, it provides more control to the replacement logic in some cases. But you can avoid it and go with @Barmar answer.

let arr = ["old", "great", "other", "long", "good", "last"];
var str = "oldgreatotherlonggoodlastfirstnewownlittle";

let re = new RegExp(arr.join("|"), "g");
let out = str.replace(re, (m) => m + " ");
console.log(out);
.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}

However, note that the previous approach only works nice on some particular situations, but for example, won't work so nice for var str = "oldotherlonglastfirstnewgoodownlittlegreat";. Then, a more generic approach would be:

let arr = ["old", "great", "other", "long", "good", "last"];
var str1 = "oldotherlonglastfirstnewgoodownlittlegreat";
var str2 = "oldgreatotherlonggoodlastfirstnewownlittle"

const separateMatches = (str, arr) =>
{
    let re = new RegExp(arr.join("|"), "g");
    let out = str.replace(re, (m) => ` ${m} `);
    return out.replace(/\s+/g, " ").trim();
}

console.log(separateMatches(str1, arr));
console.log(separateMatches(str2, arr));
.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}

Upvotes: 3

Barmar
Barmar

Reputation: 780798

Turn the array into a regular expression, and add a space before each match.

var str = "oldgreatotherlonggoodlastfirstnewownlittle";
var newstr = str.replace(/old|great|other|long|good|last/g, " $&");
console.log(newstr);
str = "greatotherlonggoodlastfirstnewownlittleold";
newstr = str.replace(/old|great|other|long|good|last/g, " $&");
console.log(newstr);

In the replacement string $& stands for whatever matched the regular expression.

Upvotes: 2

Piotr Szlagura
Piotr Szlagura

Reputation: 672

If you are looking for a way to make a regex from your array, you could do something like this:

let words = ["old", "great", "other", "long", "good", "last"];
let reg = new RegExp(words.join("|"), "g")

You can then use it with string.replace to achieve desirable effect

Upvotes: 1

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