How do I add a character at a specific position in a string?

Question

I am using Notepad++ and want to insert a character at a specific position in a string using regular expression replacement.

What would the expressions be to, say, i

Answer 1

If you want to add a character after the sixth character, simple use the search

^(.{6})

and the replacement

$1,

(Example inserts a ,)

technically spoken this will replace the first 6 characters of every line with MatchGroup 1 (backreference $1) followed by a comma.

Answer 2

Also using Vanilla Javascript

var str = 'USDYEN'
// add a / in between currencies
// var newStr = str.slice(0, 3) + ' / ' + str.slice(3)

// var newStr = str.slice(3) // removes the first 3 chars
// var newStr = str.slice(0,3) // removes the last 3 chars
var newStr = str.slice(0,3) + ' / ' + str.slice(3) // removes the first 3 and adds the last 3

console.log(newStr)

More information how to use slice()

https://www.w3schools.com/jsref/jsref_slice_string.asp