每次在jquery中获取最后一次迭代

Question

I have the following code that I am going through the tables columns and if its the last column I want it to do something different. Right now its hard coded but how can I change so it automatically knows its the last column

$(this).find('td').each(function (i) { 
    if(i > 0) //this one is fine..first column
    { 
        if(i < 4)  // hard coded..I want this to change 
        {
            storageVAR += $(this).find('.'+classTD).val()+',';
        }
        else
        {
            storageVAR += $(this).find('.'+classTD).val();
        }
    }
});

Answer 1

If you want access to the length inside the .each() callback, then you just need to get the length beforehand so it's available in your scope.

var cells = $(this).find('td');
var length = cells.length;
cells.each(function(i) {
    // you can refer to length now
});

Answer 2

It looks like your objective is to make a comma separated list of the values, why don't you collect the values and use the array method 'join'?

var values = []
$(this).find('td .' + classTD).each(function(i) {
  if (i > 0) values.push($(this).val());
});
storageVAR = values.join(',');

Answer 3

Something like this should do it:

var $this = $(this),
    size  = $this.length,
    last_index = size -1;

$this.find('td').each(function (index) { 

     if(index == 0) { 
         // FIRST

     } else if(index === last_index) {
         // LAST

     } else {
         // ALL THE OTHERS

     }

});

Answer 4

If all you want is the last column, you can use

$(this).find('td:last')

If you want to do things with other columns, go for

$(this).find('td:last').addClass("last");
$(this).find('td').each(function() {
   if ($(this).hasClass("last")) {
      // this is the last column
   } else {
      // this isn't the last column
   }
});

You can use data() instead of addclass() if you're comfortable with that.

If all you want to do is not have a comma at the end of your string, you could just chop it off afterward:

storageVAR = storageVAR.substr(0, (storageVAR.length - 1);