How to use regex in XPath "contains" function

Question

I would like to match the following text sometext12345_text using the below regex.

I'm using this in one of my selenium tests.

String expr = "//*[contains(@id, 'sometext[0-9]+_text')]";
driver.findElement(By.xpath(expr));

It doesn't seem to work though. Can somebody help?

Skepful

What version of XPath are you using? – Professor

What made you think it might work? Were you just guessing, or did you find misleading information somewhere? – Benford

@MichaelKay, I guessed that it might support. As per this, (w3.org/TR/xquery-operators/#string.match) it may not. Thanks. – Skepful

Answer 1

XPath 1.0 doesn't handle regex natively, you could try something like

//*[starts-with(@id, 'sometext') and ends-with(@id, '_text')]

(as pointed out by paul t, //*[boolean(number(substring-before(substring-after(@id, "sometext"), "_text")))] could be used to perform the same check your original regex does, if you need to check for middle digits as well)

In XPath 2.0, try

//*[matches(@id, 'sometext\d+_text')]

Professor

This seems to work: //*[boolean(number(substring-before(substring-after(@id, "sometext"), "_text")))], but it's highly specific to this use case – Hale

Yup, regex support would obviously be stronger/more flexible. Nice trick though! – Professor

seems like 'ends-with()' comes only with XPath2/XQuery but not with XPath1.0, proofs: w3.org/TR/xpath/#section-String-Functions , w3.org/TR/xpath-functions/#func-ends-with – Gerrit

How do I get to know which version of xpath is bein used in my selenium test? – Malikamalin

@Professor - could you please help me with a related question ? #44293171 – Bothnia

couldn't use ends-with in xpath 1.0, but starts-with works perfectly :) – Soddy

Answer 2

In Robins's answer ends-with is not supported in xpath 1.0 too.. Only starts-with is supported... So if your condition is not very specific..You can Use like this which worked for me

//*[starts-with(@id,'sometext') and contains(@name,'_text')]`\

Upstanding

Answer 3

If you're using Selenium with Firefox you should be able to use EXSLT extensions, and regexp:test()

Does this work for you?

String expr = "//*[regexp:test(@id, 'sometext[0-9]+_text')]";
driver.findElement(By.xpath(expr));

Hale

I'm using webdriver(2.39.0) with firefox(26.0). I tried the above suggestion but it results in error. InvalidSelectorError: Unable to locate an element with the xpath expression //*[regexp:test(@id, 'sometext[0-9]+_text')] because of the following error: [Exception... "An attempt was made to create or change an object in a way which is incorrect with regard to namespaces" code: "14" nsresult: "0x8053000e (NamespaceError)" location: "<unknown>"] Thanks for helping. – Skepful

I'm not familiar with Selenium, but if you find a way to register the namespace "http://exslt.org/regular-expressions" under the "regexp" prefix, it could work – Hale

Looks like the issue is still open for registering namespaces (code.google.com/p/selenium/issues/detail?id=1694), and it's independent of the EXSLT extensions. There are signs of people doing it here https://mcmap.net/q/243067/-how-to-extract-xml-data-using-xpath-with-selenium-webdriver ... Ah no, I think the parsing there is done outside – Hale

@paultrmbrth - - could you please help me with a related question ? #44293171 – Bothnia