Split the string based on regex pattern

Question

I am new to using regular expression. Given the string, I am trying to achieve the following:

actStr1 = 'st1/str2/str3'
expStr1 = 'str3'

actStr2 = 'str1/str2/str3 // str4'
expStr2 = 'str3 // str4'

actStr3 = 'a1/b1/c1 : c2'
expStr3 = 'c1 : c2'

In both cases, i would like to find the last string delimited by '/'

i.e, '/' like %s\/%s. delimiter '/' having strings on both sides

result1 = 'str3 // str4'
result2 = 'str3'

I tried different patterns using regex, but it incorrectly returns 'str4' delimited by '//'.

How do I avoid this?

Thanks

I think you need to show some real sample strings, your regex pattern and also the expected result.Otherwise it is a little confusing to read. — Chris Rymer
– Chris Rymer, Commented Mar 20, 2017 at 21:09
I see the solution by Casimir et Hippolyte works but you have not accepted it. I have to wonder if the use case in the initial question is practical. Why does the string have / separators // where is the string coming from in addition you have not provided the actual code with your regex. The more context you can provide the better help you will receive. — Chris Rymer
– Chris Rymer, Commented Mar 21, 2017 at 9:24

Casimir et Hippolyte · Accepted Answer · 2017-03-21 10:45:40Z

1

Instead of using String.prototype.split(), try to use String.prototype.match() to directly target what you need:

var testStrings = [ 'str1/str2/str3',
                    'str1/str2/str3 // str4',
                    'a1/b1/c1 : c2' ];

var re = new RegExp('[^/]*(?://+[^/]*)*$');

testStrings.forEach(function(elt) {
    console.log(elt.match(re)[0]);
});
/* str3
   str3 // str4
   c1 : c2 */

Less straight forward, you can also use a replacement strategy with String.prototype.replace(). The idea is to remove all until the last slash not preceded and not followed by an other slash:

var re = new RegExp('(?:.*[^/]|^)/(?!/)');

testStrings.forEach(function(elt) {
    console.log(elt.replace(re, ''));
});

edited Mar 21, 2017 at 10:45

answered Mar 20, 2017 at 20:52

Casimir et Hippolyte

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1 Comment

Casimir et Hippolyte Over a year ago

Thanks @revo, but it seems that this feature doesn't return the good array (the index of the match and the input string are missing). But In the futur I will try to use this feature.

Federico Piazza · Accepted Answer · 2017-03-20 21:33:39Z

0

You could use a regex like this:

\/(\w+(?:$| .*))

Working demo

And grab the content from capturing group

answered Mar 20, 2017 at 21:33

Federico Piazza

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Comments

Hichem ben chaabene · Accepted Answer · 2017-03-20 21:39:19Z

0

I think you can resolve this considering using arrays too!

function lastSlug(str) {
  // remove the '//' from the string
  var b = str.replace('//', '');
  // find the last index of '/'
  var c = b.lastIndexOf('/')  + 1;
  // return anything after that '/' 
  var d = str.slice(c);
  return d;
}

Demo

answered Mar 20, 2017 at 21:39

Hichem ben chaabene

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