Hi I have a varying URL similar to:
http://farm4.staticflickr.com/3877/[image_id]_[secret].jpg
e.g. http://farm4.staticflickr.com/3877/14628998490_233a15c423_q.jpg
I need to extract image_id that's first set of numbers (i.e. 14628998490) before an underscore from 14628998490_233a15c423_q.jpg between the whole URL
Is there a good way to extract image_id?
Right now I am going to use:
var image_id = image_url.match(/[\/]([0-9]+)_/)[1]
Like i said in the comment, you don't need to escape / symbol in the character class. And also you don't need even a character class also. Just \/ would be enough. The below regex would capture one or more numbers which are preceded by / symbol and followed by _ symbol.
\/(\d+)_
> var image_id = image_url.match(/\/(\d+)_/)[1]
undefined
> image_id
'14628998490'
OR
You could try this also, if you don't want to give \d+ in your pattern.
\/([^/]*?)_
> var image_id = image_url.match(/\/([^/]*?)_/)[1]
undefined
> image_id
'14628998490'
/ in the char class.Not shure that it's is better way, but you can do like this:
var str = 'http://farm4.staticflickr.com/3877/[image_id]_[secret].jpg';
var image_id = str.split('/').pop().split('.')[0].split('_');
If the special character is always the same (_), you could first obtain the last part (width substring+lastIndexOf) and then use split() :
var url = "http://farm4.staticflickr.com/3877/14628998490_233a15c423_q.jpg";
var splittedUrl = url.substr(url.lastIndexOf('/')+1).split("_");
var image_id = splittedUrl[0];
console.log(image_id);
I've read somewhere that string functions are faster than regexp, so it's an option you might consider.
String splitting is faster tha regex.You can just get the last index of / and string between first occurence of _ after last occurence of /. I think that will be better idea.
/in the character class. you don't need even a character class also. Just\/would be enough.image_idcontains numbers. It won't works if it contains alphanumeric charcters or anything else.