Use Regular Expressions QTP

Posted by rajivkumarnandvani on May 5, 2009

Some Times QTP does not recognize the application object during second run  Or it run first time successfully then QTP gives an error cannot identified the application Window object properties does not match with the test object. There might be a case of window name /object name is getting changed each time. Here we required the use of regular expression. See the below example for more clarification

Regular Expression

Regular Expression

During Recording of  Flight application QTP record the flight application it identified the Fax order window name property like this

It Text Property is Fax order 11

If you run this script Again it will give an error because Fax order Window name will be

Fax order 12



Cannot identify the object “Fax Order No. 11” (of class Dialog). Verify that this object’s properties match an object currently displayed in your application.

Line (1): “Window(“Flight Reservation”).Dialog(“Fax Order No. 11″).Activate”.

Now we change text property to regular expression open Object properties from object repository  .Click on text property value cell



Check regular expression check box A message will appear click NO. Now change Text box value according to Regular expreesion.

Fax Order No. 11 to Fax Order No.*

Here each time only last part getting changed here we use .* as regular expression means it will check only Fax order No text not whole string

Same case we can  apply for different object properties if they are getting changed

A regular expression is a string that describes or matches a set of strings. It is often called a pattern as it describes set of strings.

Given underneath is one of the most widely used and ever confused BackLash character. The remaining expressions are serialized below that.

Using the Backslash Character
A backslash (\) instructs QuickTest to treat the next character as a literal character, if it is otherwise a special character. The backslash (\) can also instruct QuickTest to recognize certain ordinary characters as special characters. For example, QuickTest recognizes \n as the special newline character.
For example:
w matches the character w
\w is a special character that matches any word character including underscore
For example, in QTP, while entering the URL of a website,
The period would be mistaken as an indication of a regular expression. To indicate that the period is not part of a regular expression, you would enter it as follows:
mercurytours\.mercuryinteractive\.com Note: If a backslash character is used before a character that has no special meaning, the backslash is ignored. For example, \z matches z.

Expressions & Explanation
Special characters and sequences are used in writing patterns for regular expressions. The following describes the characters and sequences that can be used\
Marks the next character as either a special character or a literal. For example, “n” matches the character “n”. “\n” matches a newline character. The sequence “\\” matches “\” and “\(” matches “(“.

Matches the beginning of input.

Matches the end of input.

Matches the preceding character zero or more times. For example, “zo*” matches either “z” or “zoo”.

Matches the preceding character one or more times. For example, “zo+” matches “zoo” but not “z”.

Matches the preceding character zero or one time. For example, “a?ve?” matches the “ve” in “never”.

Matches any single character except a newline character.

Matches pattern and remembers the match. The matched substring can be retrieved from the resulting Matches collection, using Item [0]…[n]. To match parentheses characters ( ), use “\(” or “\)”.

Matches either x or y. For example, “zwood” matches “z” or “wood”. “(zw)oo” matches “zoo” or “wood”.

n is a nonnegative integer. Matches exactly n times. For example, “o{2}” does not match the “o” in “Bob,” but matches the first two o’s in “foooood”.

n is a nonnegative integer. Matches at least n times. For example, “o{2,}” does not match the “o” in “Bob” and matches all the o’s in “foooood.” “o{1,}” is equivalent to “o+”. “o{0,}” is equivalent to “o*”.

m and n are nonnegative integers. Matches at least n and at most m times. For example, “o{1,3}” matches the first three o’s in “fooooood.” “o{0,1}” is equivalent to “o?”.

A character set. Matches any one of the enclosed characters. For example, “[abc]” matches the “a” in “plain”.

A negative character set. Matches any character not enclosed. For example, “[^abc]” matches the “p” in “plain”.

A range of characters. Matches any character in the specified range. For example, “[a-z]” matches any lowercase alphabetic character in the range “a” through “z”.

A negative range characters. Matches any character not in the specified range. For example, “[m-z]” matches any character not in the range “m” through “z”.

Matches a word boundary, that is, the position between a word and a space. For example, “er\b” matches the “er” in “never” but not the “er” in “verb”.

Matches a non-word boundary. “ea*r\B” matches the “ear” in “never early”.

Matches a digit character. Equivalent to [0-9].

Matches a non-digit character. Equivalent to [^0-9].

Matches a form-feed character.

Matches a newline character.

Matches a carriage return character.

Matches any white space including space, tab, form-feed, etc. Equivalent to “[ \f\n\r\t\v]”.

Matches any nonwhite space character. Equivalent to “[^ \f\n\r\t\v]”.

Matches a tab character.

Matches a vertical tab character.

Matches any word character including underscore. Equivalent to “[A-Za-z0-9_]”.

Matches any non-word character. Equivalent to “[^A-Za-z0-9_]”.

Matches num, where num is a positive integer. A reference back to remembered matches. For example, “(.)\1” matches two consecutive identical characters.

Matches n, where n is an octal escape value. Octal escape values must be 1, 2, or 3 digits long. For example, “\11” and “11” both match a tab character. “011” is the equivalent of “01” & “1”. Octal escape values must not exceed 256. If they do, only the first two digits comprise the expression. Allows ASCII codes to be used in regular expressions.

Matches n, where n is a hexadecimal escape value. Hexadecimal escape values must be exactly two digits long. For example, “\x41” matches “A”. “\x041” is equivalent to “\x04” & “1”. Allows ASCII codes to be used in regular expressions


22 Responses to “Use Regular Expressions QTP”

  1. vinod said

    You are really doing great job. Please keep it up

  2. Thanks man

  3. Pierloot said

    I’m using QTP 9.5 with a Windows application.
    Each time QTP starts the application, the ‘regexpwndtitle’ field (object property) is suffixed by ‘_x’ where x is a number.
    This means that if the test is ran many time, the Windows application is not recognized by QTP.
    I checked the ‘regular expression’ in ‘object property’ dialog but the test still stops on the windows with the message ‘cannot recognize the windows…’
    Can you help me ?

  4. try this _.*
    replace your number after underscore with dot star.and make sure your regulerexpression checkbox is checked. Check regular expression check box A message will appear, click NO.

  5. Pierloot said

    I realized I made a mistake.The ‘regexpwndtitle’ field always contains the same value.
    Let me explain what happens.
    I open my application, record and stop recording after one click.
    In the ‘expert’ view, I see for example : Window(“Cost Accountancy”).Click 243,64
    I open again my application, record and stop after another click.
    In the ‘expert’ view, I have now 2 lines: the previous one and this one: Window(“Cost Accountancy_2”).Click 243,64
    I run the test, I receive an error because “Windows Cost Accountancy” is not found.
    This is my problem.
    Thanks a lot for your help.

  6. Hi Jean,

    It seems QTP is not identifying the object of your application. Instead of Recording, try first with Object spy Is Object spy identyfing the Object properties or Not. It could be an issue of addin like if your application built in WPF control OR java aaaplication etc in that case you must have appropriate add-in loaded like Wpf, Java,sebiel etc.. You can take the help from developer to know your application platform.

    Thanks & Best of luck

  7. Jean-Claude Pierloot said

    I’m back again.
    I used Object Spy after launching 3 occurrences of my application.
    The Regexpwndtitle is “myapplication” for each occurrence (3 screens).
    If I record a click in each screen, the Expert view shows:
    I tried to replace ‘2’ and ‘3’ by .* and the following error is displayed:
    “The “myapplication_.*” Window object was not found in the Object Repository.
    Check the Object Repository to confirm that the object exists or to find the correct name for the object..”

    What do you suggest ?
    Again I thank you for your help.

  8. rajivkumarnandvani said

    Hi jean,

    That is logical name you are changing that one. First you have to identify the property of window through object repository/object spy which is changing each time. use regular expression for that property in OR. Property could be any thing which is changing like name, title etc..

    Best of luck

  9. kk said

    you r really doing great clear picture about regular expressions.thx….a lot!!!

  10. rajivkumarnandvani said

    Thanks for reading the blog 🙂

  11. Swapna said

    Doing great job!!!
    How to pass regular expression for dynamic link in the application
    please suggest

  12. rajivkumarnandvani said

    Hi Swapna,
    Thanks for reading the blog.
    For dynamic link First you have to analysis of link property which is getting changed regularly, use regular expresion for this like if link text name is getting changed but rest property is fixed, you can use regular expression for text property of link.

    I hope it make you clear the use of regular expression.
    Best of luck

  13. Anonymous said

    I am prakash,
    really u r job is good and it is very useful for many people, i have tried this regular expression logic for many applications

  14. Hi Prakash,
    Thanks for reading the blog.

  15. Anonymous said

    found your blog. you helped me solve a “show stopper.” thanks so much.

  16. Anonymous said

    hi nice work

  17. Arpita said

    Hi Rajiv,

    Could you please help me , im stuck at my project work .

    Im using Regular expression like WebPage[\_*] when the WebPage object is dynamic in nature:


    is it the correct way of using?

  18. rajivkumarnandvani said

    Try this one..

  19. Manu said

    Could you help me to write regular expression for the following.



  20. sai said

    Wow its clear n useful…thank u

  21. Anonymous said

    Hi rajivkumarnandvani,

    Great job We can able to implement in our application Please keep posting we expecting more from U

  22. nagaraju said

    hi sir
    could you plz tell me how to write regular expressions for foll following mobile numbers

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