多个id进行hover事件问题

我想实现鼠标移动到相应id/class的div字体高亮和变大小,需要变大小的class名是相应高亮的id名加上字符串'bar',比如:
高亮的id名为a,则相应的变大小class名为bar-a
代码:

<div id="a">aaa</div>
<div id="b">bbb</div>
.....

<div class="bar-a">32</div>
<div class="bar-b">22</div>
....

<script>
var arr=["#a","#b",....]
var b="";
for (var i in arr) {
    $(arr[i]).hover(
        function () {
//mouseover
            $(this).css({"opacity": "1"});
            b = arr[i].substr(1);
            b = ".bar-" + b;
            $(b).css({"font-size": "20px"});
        }, function () {
//mouseout
            $(this).css({"opacity": "0"});
            b = arr[i].substr(1);
            b = ".bar-" + b;
            $(b).css({"font-size": "14px"})
        })
}
</script>

我想问的是,上面的高亮能正常显示,但是变大小的仅数组最后一个元素的class相应div会变,其他都不会,不知道错在哪了。每接触多久js,望哥哥们帮助,谢谢!

<!DOCTYPE html>
<html>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no">
    <meta name="format-detection" content="telephone=no">
<script src="http://code.jquery.com/jquery-3.4.1.min.js"></script>
<style>
    .on{opacity:1;color:red}
    .active{font-size:20px;}
</style>
<div class="a" id="a">aaa</div>
<div class="a" id="b">bbb</div>
.....

<div class="bar-a">32</div>
<div class="bar-b">22</div>
....

<script>
    $(".a").hover(
        function () {
//mouseover
            var obj=$(this).attr("id");
            $(this).addClass("on");
            $(".bar-"+obj).addClass("active");
        }, function () {
//mouseout
            $(this).removeClass("on");
            var obj=$(this).attr("id");
            $(".bar-"+obj).removeClass("active");
        })

</script>
</html>
   b = arr[i].substr(1);//应该是b
   b = ".bar-" + b;//应该是.bar-b

这段你输出下b,
然后jq找到对应的类,看代码里面只有

<div class=".bar-b">这个会变,