Regular Expressions in QTP
REGULAR EXPRESSIONS REGULARIZED:
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
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. [^abc]
$ : 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.
(pattern) :
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 "\(" or "\)".
xy :
Matches either x or y. For example, "zwood" matches "z" or "wood". "(zw)oo" matches "zoo" or "wood".
{n} :
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,}
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*".
{n,m}
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?".
[xyz]
A character set. Matches any one of the enclosed characters. For example, "[abc]" matches the "a" in "plain".
[^xyz]
A negative character set. Matches any character not enclosed. For example, "[^abc]" matches the "p" in "plain".
[a-z]
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".
[^m-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".
\d :Matches a digit character. Equivalent to [0-9].
\D :Matches a non-digit character. Equivalent to [^0-9].
\f :Matches a form-feed character.
\n :Matches a newline character.
\r :Matches a carriage return character.
\s :Matches any white space including space, tab, form-feed, etc.
\S :Matches any nonwhite space character.
\t :Matches a tab character.
\v :Matches a vertical tab character.
\w
Matches any word character including underscore. Equivalent to "[A-Za-z0-9_]".
\W
Matches any non-word character. Equivalent to "[^A-Za-z0-9_]".
\num
Matches num, where num is a positive integer. A reference back to remembered matches. For example, "(.)\1" matches two consecutive identical characters.
Regular Expression
Objects and text strings with varying (changeable) values can be identified by QuickTest using Regular expressions.
Regular expressions can be used:
to define property values of an object.
to parameterize a step.
to create a checkpoint with changeable values.
Important points regarding Regular expressions:
You can use regular expressions only for values of type string.
When any special character in a regular expression is preceded by a backslash (\), QuickTest searches for the literal character.
You can define a regular expression for a constant value, a Data Table parameter value.
1. Regular Expression and Property Values of Objects.
2. Regular Expression and Checkpoints
3. Regular Expression and Data Table.
A regular expression is a string that specifies a complex search phrase. By using special characters such as a period (.), asterisk (*), caret (^), and brackets ([ ]), you define the conditions of the search.
we can write the user defined in a notepad and save the file as .vbs and we then associate that to Test-Settings-Resources-Associate Library Files by clicking plus and select the .vbs file. In the script we can call the function with function name ().
