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Not getting a new line in kotlin text view on android studio

fun SubmitOrder(view: View) {
/* pricing of coffee */
val total = quantity * 5
val s: String = ("$$total.00")
money.text = ("Total : $s\nThank You!").toString()
//This is calling On click listener
Toast.makeText(this, "order_Submitted", Toast.LENGTH_SHORT).show()
}
In this code, I need a new line before Thank You! in money.text but I am not getting any new line I am new in android development so, am not able to point out the mistake.

Let's go thru your code line by line:
val s: String = ("$$total.00")
s is a bad variable name, as it's not descriptive at all
you don't need the (braces)
the :String here is optional. In such an obvious case i would emit it.
A $ is a sign to the kotlin compiler to include the following variable. Therefore, you can't use the $ when you mean "US-Dollar". See this post on how to escape it
While ".00" works, it's no good style. I suggest you use string formatting as described here.
can be written as val s = "\$ ${String.format("%.2f", total)}"
you should wherever possible use string resources, but thats out of the scope of this answer
money.text = ("Total : $s\nThank You!").toString()
this is correct, but unnecessary verbose:
"Total : $s\nThank You!" is already a string, so there's no need to .toString()
braces are not needed
can be written as money.text = "Total : $s\nThank You!"

Format number in kotlin with commas

I'm pretty new to kotlin and would like to know how to format a number with commas.
Currently, my textview shows a number without any commas, i.e, 15000.
I want it to show 15,000 instead.
Here's my code that I want to format:
txtTotalActive.text = it.statewise[0].active
"it.statewise[0].active" is an object that shows number but as I said, it shows without any commas.

Solution:
var inoutValue = it.statewise[0].active
val number = java.lang.Double.valueOf(inoutValue)
val dec = DecimalFormat("#,###,###")
val finalOutput = dec.format(number)
txtTotalActive.text = finalOutput

"%,.2f".format(text.toFloat()) <,> = grouping , 2 = precision/number of decimals after "."

Kotlin check for words in string

I have a NSFW class that scans texts like item names and descriptions against a list of known NSFW-words.
That would be the best approach to test a list of strings like
let nsfw = listof(
"badword",
"curseword",
"ass",
... 200+ more
)
against a string like:
This is the text that contains a badword // returns true
Please note that i need to check for full words. not parts of words.
so the sentence:
The grass is grean // returns false
Because grass is not a bad word.
Ive tried something like this but it doesnt check for full words.
val result = nsfw.filter { it in sentence.toLowerCase() }

You may build a regex like
\b(?:word1|word2|word3...)\b
See the regex demo. Then, use it with the Regex.containsMatchIn method:
val nsfw = listOf(
"badword",
"curseword",
"ass"
)
val s1 = "This is the text that contains a badword"
val s2 = "The grass is grean"
val rx = Regex("\\b(?:${nsfw.joinToString(separator="|")})\\b")
println(rx.containsMatchIn(s1)) // => true
println(rx.containsMatchIn(s2)) // => false
See this Kotlin demo.
Here, nsfw.joinToString(separator="|") joins the words with a pipe (the alternation operator) and the "\\b(?:${nsfw.joinToString(separator="|")})\\b" creates the correct regex.
If your words may contain special regex metacharacters, like +, ?, (, ), etc., you need to "preprocess" the nsfw values with the Regex.escape method:
val rx = Regex("\\b(?:${nsfw.map{Regex.escape(it)}.joinToString("|")})\\b")
^^^^^^^^^^^^^^^^^^^^^^
See the Kotlin demo.
AND one more thing: if the keywords may start/end with chars other than letters, digits and underscores, you cannot rely on \b word boundaries. You may
Use whitespace boundaries: val rx = Regex("(?<!\\S)(?:${nsfw.map{Regex.escape(it)}.joinToString("|")})(?!\\S)")
Use unambiguous word boundaries: val rx = Regex("(?<!\\w)(?:${nsfw.map{Regex.escape(it)}.joinToString("|")})(?!\\w)")

You can use split() on the string that you want to check, with space as a delimiter, so you create a list of its words, although this does not always guarantee that all words will be extracted successfully, since there could exist other word separators like dots or commas etc. If that suits you, do this:
val nsfw = listOf(
"badword",
"curseword",
"ass"
)
val str = "This is the text that contains a badword"
val words = str.toLowerCase().split("\\s+".toRegex())
val containsBadWords = words.firstOrNull { it in nsfw } != null
println(containsBadWords)
will print
true
If you want a list of the "bad words":
val badWords = words.filter { it in nsfw }

How to detect #mentions in Kotlin using regex?

I need help in matching the #mentions words which itself contains some ids which will be used to redirect users to particular userId.
Here is my string:
val string = "Hello #[%user%]Akash(ef54321). Is #[%user%]Shubham(45321gg) there with you?"
I need parsed response == "Hello #Akash. Is #Shubham there with you?"
Also onClick of #Akash And #Shubham I need ids which are there in format (xxxxx).And #mentions should appear in grey background.Any help would be highly appreciated.Thanks,
I am using
val string = "Hello #[%user%]Akash(54321).Is #[%user%]Shubham(543215) there with you "
val matcher = Pattern.compile("^[#]\\w+|(?<=\\s)[#]\\w+").matcher(string)
while (matcher.find()) {
println("TAG"+matcher.group())
}

You may use
val string = "Hello #[%user%]Akash(ef54321). Is #[%user%]Shubham(45321gg) there with you?"
val rx = Regex("""#\[%user%](\w+)\((\w+)\)""")
val res = string.replace(rx, "#$1")
println(res) // => Hello #Akash. Is #Shubham there with yo?
val users =rx.findAll(string).map{it.groups[1]!!.value}.toList()
val ids =rx.findAll(string).map{it.groups[2]!!.value}.toList()
println(users) // => [Akash, Shubham]
println(ids) // => [ef54321, 45321gg]
See the Kotlin demo.
The #\[%user%](\w+)\((\w+)\) regex contains two capturing groups for users and for IDs. In the replacement method, you may refer to those values using $1 and $2 placeholders.
Pattern details
#\[%user%] - a #[%user%] literal string
(\w+) - Capturing group 1 (user, $1): one or more letters, digits or underscores
\( - a ( char
(\w+) - Capturing group 2 (ID, $2): one or more letters, digits or underscores
\) - a ) char.

Add only 1 char into String

Is it possible to change 1 char into String from code in Kotlin ?
I think yes, but I don't know how.
<string name="carID">Id: </string>
Currently I change whole String like:
carID.text = car.id.toString()
but I want add only number to this ID:

You can convert a char to a string:
val myChar = '1'
val myString = Character.toString(myChar )
Now, you can concat the new string to your other string:
val myIdString = "Id: $myString"
This is of course just the mechanics, you will need to adapt the code as you need and of course there are short-cuts if you want: this was purely for demonstration.

Change your string resource like this:
<string name="carID">Id: %1$s</string>
and you use it:
carID.text = String.format(getString(R.string.carID), "1")
the text will be: Id: 1