'How to add a full stop to the end of a string, except if there is question mark, exclamation mark or semicolon?

This works for full stop only:

if (string.charAt(string.length-1) != ".") {
        string = string+".";
};

javascript

Solution 1:^[1]

just add extra conditions into your 'if' statement to say "is not a . or a ? or a ! or a ;

Solution 2:^[2]

You can use this way :

<!DOCTYPE html>
<html>
<body>
<p id="demo">Click the button to display the first character of a string.</p>
<button onclick="myFunction()">Try it</button>
<script>
function myFunction()
{
var str = "HELLO WORLD?";
if(str.charAt(str.length-1) != "." && str.charAt(str.length-1) != "?" && str.charAt(str.length-1) != "!" && str.charAt(str.length-1) != ";")
document.getElementById("demo").innerHTML=str+".";
else
document.getElementById("demo").innerHTML=str;
}
</script>
</body>
</html>

Solution 3:^[3]

For one condition, you could do this:

if(!~[".","!","?",";"].indexOf(string[string.length-1])) string+=".";

Explanation:

the tilde operator (~): ~x is equivalent to -Math.floor(x)-1 that means that if the last character isn't one of [".","!","?",";"], indexOf returns -1, which the tilde operator changes to 0, which, when negated, gives true (because it is falsy) !0 == false

string[x] is equivalent to string.charAt(x)

Solution 4:^[4]

const addPeriodMark = (str) => {
  return str.endsWith(".") ? str : str + ".";
};

Use endWith() for condition.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	M21B8
Solution 2
Solution 3
Solution 4	Penguin

'How to add a full stop to the end of a string, except if there is question mark, exclamation mark or semicolon?

Solution 1:[1]

Solution 2:[2]

Solution 3:[3]