Check, if word has a same end and start in JavaScript

Question

I'm searching for how can I check if word has a same end and start. There is my code:

JavaScript:

function Check() {
  var value = document.getElementById("input").value;

  if (value == startsWith(endsWith()) && value == endsWith(startsWith())) {
    return alert("Yes");

  } else {
    return alert("No");
  }
}

<input id="input" style="margin:20px;" type="text"><br>
<button id="button" onclick="Check();">Check</button>
<p id="demo" style="color:white;">Answer</p>

both startsWith and endsWith methods checking first and last character of string ? explain it . — Siva Rm K, May 22 '18 at 05:44
Did you mean starting and ending with the same character (eg, `Level`) ? Then, you should try `if(value[0] == value[value.length-1]) { alert('Yes'); } else { alert('No'); }` — , May 22 '18 at 05:44
does start and end mean the same letter? or the same word? or the same 3 letters? or something completely else? — Sergej, May 22 '18 at 05:45
Mayme you mean [palindrome](https://stackoverflow.com/questions/31090974/check-if-a-string-is-a-palindrome-in-javascript/31091045#31091045) — Walter Chapilliquen - wZVanG, May 22 '18 at 05:52

score 2 · Answer 1 · answered May 22 '18 at 05:47

2

Just check the first and last character of the string:

if(value[0] == value[value.length-1]) 
{
   alert('Yes');
}
else
{ 
   alert('No');
}

answered May 22 '18 at 05:47

Harsh Jaswal

447
3
14

Glad to solve your problem. Please mark it as answer. :) – Harsh Jaswal May 22 '18 at 05:55

Yogesh Patel · Accepted Answer · 2018-05-22T05:51:19.263

1

Try below function. I am comparing first character and last character of your input string.

function Check() {
  var value = document.getElementById("input").value;

  if (value.charAt(0) === value.charAt(value.length - 1)) {
    return alert("Yes");

  } else {
    return alert("No");
  }
}

edited May 22 '18 at 05:51

answered May 22 '18 at 05:47

Yogesh Patel

818
2
12
26

This one works thanks, but alert("No"); is not working – May 22 '18 at 05:50
Edited. Now check. – Yogesh Patel May 22 '18 at 05:51
Please mark as answer or up vote. So others can use it easily. – Yogesh Patel May 22 '18 at 05:55

Matus Dubrava · Answer 3 · 2018-05-22T05:55:23.597

Use str.length - 1 to get the index of the last character of the string.

function check(str) {
  if (str[0] === str[str.length - 1]) {
    alert('yes')
  } else {
    alert('no');
  }
}

check('test');
check('tests');

To check first/last n characters you can do this.

function checkMore(str, amount) {
  if (str[0] !== str[str.length - 1]) {
    alert('no');
    return;
  } else if (amount !== 1) {
    return checkMore(str.slice(1, str.length - 1), amount - 1);
  }
  alert('yes');
}

checkMore('stests', 1);
checkMore('stests', 2);
checkMore('stests', 3);

And to check the whole string (basically checking if the string is palindrome).

function checkPalindrome(str) {
  if (str.length === 0 || str.length === 1) {
    alert('yes');
    return;
  }
  if (str[0] !== str[str.length - 1]) {
    alert('no');
    return;
  }
  checkPalindrome(str.slice(1, str.length - 1));
}

checkPalindrome('car');
checkPalindrome('carac');
checkPalindrome('carrac');

Thanks for your work, I appreciate that, but I already found my answer. — , May 22 '18 at 06:00

score 1 · Answer 4 · answered May 22 '18 at 06:07

You can use match() or indexOf(). Both work, but both search the whole string. It is more efficient to extract the substring in the relevant place and compare it with the one you expect there:

function Check ( word ) {
  return word.charAt(0) == word.charAt( word.length - 1 )
}

<button tye="button" onclick="alert( Check('Hello') )">Check 'Hello'</button>
<button tye="button" onclick="alert( Check('HelloH') )">Check 'HelloH'</button>

Of course, you might as well use a regular expression, with a smart regex engine it should be efficient as well (and your code is more concise):

function Check ( word ) {
  return /^(.).*\1$|^.$/.test( word )
}

<button tye="button" onclick="alert( Check('Hello') )">Check 'Hello'</button>
<button tye="button" onclick="alert( Check('WoW') )">Check 'WoW'</button>

score 0 · Answer 5 · answered May 22 '18 at 05:47

0

var value = "wow"
return (value[0] === value[value.length - 1] ? true : false)

0th index will contain starting character and value.length - 1 will contain ending character. If they are equal it will return true and false otherwise.

answered May 22 '18 at 05:47

Niragh

162
2
10

score 0 · Answer 6 · answered May 22 '18 at 05:50

You can use .split('' ) to split a string by spaces, so into words. It splits it into an array, so you can compare index [0] to index [length-1]

For example

    function Check(string) {
        let arr = string.split(' ');
        return arr[0] == arr[arr.length-1];
    }

score 0 · Answer 7 · answered May 22 '18 at 05:51

0

Use regex:

if (/^(.).*\1$|^.$/.test(value))
    // first and last are same letter

answered May 22 '18 at 05:51

Bohemian

412,405
93
575
722

Check, if word has a same end and start in JavaScript

7 Answers7