I got a few names of automatically generated folders on a site.

They are named like this:

"folder_photos_today_1"
"folder_photos_yesterday_2"
"folder_photos_future_3"
...
"folder_potos_more_11"

The number at the end of each name is an ID for the folder, thats generated by a Plugin.

Now I'd like to display these folder-names like:

"folder photos today"
"folder photos yesterday"

Converting the names with javascript (pureJS or jQuery, doesn't matter) I thought about finding the last _ in the name and deleting it and everything after it. Then search for other _ and replace them with whitespaces.

The problem I have: How do I find the last character of one type (the last _) with JS?

I got a few names of automatically generated folders on a site.

They are named like this:

"folder_photos_today_1"
"folder_photos_yesterday_2"
"folder_photos_future_3"
...
"folder_potos_more_11"

The number at the end of each name is an ID for the folder, thats generated by a Plugin.

Now I'd like to display these folder-names like:

"folder photos today"
"folder photos yesterday"

Converting the names with javascript (pureJS or jQuery, doesn't matter) I thought about finding the last _ in the name and deleting it and everything after it. Then search for other _ and replace them with whitespaces.

The problem I have: How do I find the last character of one type (the last _) with JS?

• javascript
• jquery
• string
• text
• replace

3 Answers 3

lastIndexOf() is what you want:

var index = "folder_photos_future_3".lastIndexOf('_');  // returns 20

You can then substring and replace your _ with spaces.

You could also split() your string and discard the last value:

var words = "folder_photos_future_3".split('_');
words.pop();
words.join(' '); // "folder photos future"

Wouldn't be this oneliner simpler?

"folder_photos_today_12".replace(/_[0-9]+/g,"").replace(/_/g," ");

http://jsfiddle/sf2p4yua/

Here are some explanations:

.replace(/_[0-9]+/g,"") 

replaces the bination of underscore and more that one digit after, so you'll have this string folder_photos_today.

.replace(/_/g," ")

replaces all underscores inside the string: folder photos today.

Hope this plunker link will help you.

http://plnkr.co/edit/V1hFEt37GzVq7AYUVUMa?p=preview

var splitFunction = function(){

var arr = ["folder_photos_today_1",
"folder_photos_yesterday_2",
"folder_photos_future_3",
"folder_photos_four_4",
"folder_photos_five_5",
"folder_photos_six_6",
"folder_photos_seven_7",
"folder_photos_eight_8",
"folder_photos_nine_9",
"folder_photos_ten_10",
"folder_potos_more_11"];

var res = [];

document.getElementById('result').innerHTML = "<b>RESULT : </b><br/>"
for (var i =0; i<arr.length; i++){
  res[i] = arr[i].substr(0,arr[i].lastIndexOf('_'));
 res[i] = res[i].replace(/_/g, ' ');
 document.getElementById('result').innerHTML += res[i] + '<br/>';
}

}