javascript for checking alphabets from a string

Question

I have a string which is of format 245545g65.

var value = "245545g65"  
var last3Letters = value.substring(7,9);  // abc

Now I want to validate whether the last three letters contains only alphabets, if it is alphabet , i want to alert it.how to alert g?

how do i do this?

i only want characters from string and that to only from last three letter, not any numbers — Irfan, Jul 01 '13 at 17:02
I believe you want something like this: http://regexr.com?35dsb — David Starkey, Jul 01 '13 at 17:03

score 5 · Accepted Answer · answered Jul 01 '13 at 17:02

assuming that "contains only alphabets" means the last three characters are a combination of the letters a-z:

var str = '245545g65';
if (/[a-z]{3}$/.test(str)){
  // last three characters are any combinations of the letters a-z
  alert('Only letters at the end!');
}

sora0419 · Answer 2 · 2013-07-01T17:07:27.893

0

you can use isNaN to check weather s string is number

if (!isNan(last3Letters))
    alert(last3Letters + ' is number.')
else
    alert(last3Letters + ' is not number.')

edited Jul 01 '13 at 17:07

answered Jul 01 '13 at 17:02

sora0419

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The non-numeric character may not be in the last 3 characters of the string. – David Starkey Jul 01 '13 at 17:05
So if `isNaN()` is `true`, it's a number?? – Jul 01 '13 at 17:05
@David- but he's checking the last 3 characters right?@CrazyTrain - missing !, thanks for pointing that out, I've edited my answer. – sora0419 Jul 01 '13 at 17:08
Trouble is that this only guarantees that it can't be converted to a number, not that it has all letters. For example `"q5A"` will fall into the category of "not a number", but it still has a number. OP wants to guarantee 3 letters. – Jul 01 '13 at 17:11

score 0 · Answer 3 · edited May 23 '17 at 10:32

0

Easy:

var alpha = /^[A-z]+$/;
alpha.test(last3Letters);

This will return a boolean (true/false). Stolen from here.

edited May 23 '17 at 10:32

Community

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answered Jul 01 '13 at 17:02

PlantTheIdea

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How will this work in his example with a g then 2 numbers? Also, this would work with just 1 or 2 letters at the end. – David Starkey Jul 01 '13 at 17:04
@DavidStarkey: This answer is testing the last 3 characters, and is anchored to the start and end of that substring. It'll only pass if there are all letters. – Jul 01 '13 at 17:14

score 0 · Answer 4 · answered Jul 01 '13 at 17:04

0

you can use RegEx and compare length

var re = new RegExp("[^0-9]*", "g");
var newlast3Letters =last3Letters.replace(re,"");
if(newlast3Letters.length!=last3Letters.length)
{
 alert("not all alphabets");
}
else
{
 alert("all alphabets");
}

answered Jul 01 '13 at 17:04

Bhushan Kawadkar

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score 0 · Answer 5 · answered Jul 01 '13 at 17:10

0

You can also do this:

var value = "245545g65"  
if(value.slice(value.length-3).search(/[^a-z]/) < 0) {
    alert("Just alphabets");
} else {
    alert("Not just alphabets");
}

answered Jul 01 '13 at 17:10

DarkAjax

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javascript for checking alphabets from a string

5 Answers5