JSFiddle - React, Tailwind, and code Playground

HTML

<div class="myClass" data-p="2">7</div>
<div class="myClass" data-p="3">8</div>
<div class="myClass" data-p="4">9</div>
<div class="myClass" data-p="5">4</div>
<div class="myClass" data-p="6">5</div>

JavaScript

/* $(".myClass").each(function(i){
    if(i%2==0){
        $(this).data('myAttr',i+1);                
    }
});
    
$('.myClass').each(function(i){
    console.log($(this).data('myAttr'));
}); */    
    
//Solution
var e = $('[data-p]')
e.each(function(pp){
	console.log(pp);
	console.log(pp.data('p'));
});
//var elements=$('.myClass').filter(function(){return $(this).data('myAttr') !== undefined;} */);

//console.log(elements);