A Regular Expression is a string that describes or matches a set of strings, according to certain syntax rules. A Regular Expression often called a pattern is an expression that describes a set of strings.
Regular Expressions enable QuickTest to identify objects and text strings with varying values.
We can use Regular Expressions in the below situations,
1. Property Value for a particular object is varying frequently.
2. Parameterizing a step.
3. Creating checkpoints with varying values.
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. Example: QuickTest recognizes \n as the special newline character.
Example:
\\ matches the literal character \
\ (matches the literal character (
Matching Any Single Character:
A period (.) instructs QuickTest to search for any single character (except for \n).
For example:
Welcome. matches Welcomes, Welcomed, or Welcome followed by a space or any other single character.
A series of periods indicates the same number of unspecified characters.
To match any single character including \n, enter: (.|\n)
Matching Any Single Character in a List:
Square brackets instruct QuickTest to search for any single character within a list of characters.
Example, to search for the date 2000, 2001, or 2002, enter: 200[012]
Matching Any Single Character Not in a List Iterative constructs:
When a caret (^) is the first character inside square brackets, it instructs QuickTest to match any character in the list except for the ones specified in the string.
Example: [^ab] matches any character except a or b.
Note: The caret has this special meaning only when it is displayed first within the brackets.
Matching Any Single Character within a Range
In order to match a single character within a range, you can use square brackets ([ ]) with the hyphen (-) character.
Example: To match any year in the 2000s, enter: 200[0-9]
Matching Zero or More Specific Characters Functions and subroutines
An asterisk (*) instructs QuickTest to match zero or more occurrences of the preceding character.
For example: ca*r matches car, caaaaaar, and cr.
Matching One or More Specific Characters
A plus sign (+) instructs QuickTest to match one or more occurrences of the preceding character.
Example: ca+r matches car and caaaaaar, but not cr.
Matching Zero or One Specific Character
A question mark (?) instructs QuickTest to match zero or one occurrences of the preceding character.
Example: ca?r matches car and cr, but nothing else.
Grouping Regular Expressions
Parentheses (()) instruct QuickTest to treat the contained sequence as a unit, just as in mathematics and programming languages.
Using groups is especially useful for delimiting the argument(s) to an alternation operator ( | ) or a repetition operator ( * , + , ? , { } ).
Matching One of Several Regular Expressions
A vertical line (|) instructs QuickTest to match one of a choice of expressions.
For example:
Too|bar causes QuickTest to match either Too or bar.
To(o|b)ar causes QuickTest to match either Tooar or Tobar.
Matching the Beginning of a Line:
A caret (^) instructs QuickTest to match the expression only at the start of a line, or after a newline character.
Example:
Phone matches Phone within the lines—Phone, my Phone, and Phone list, while
^ Phone matches Phone only in the lines—Phone and Phone Numbers.
Matching the End of a Line
A dollar sign ($) instructs QuickTest to match the expression only at the end of a line, or before a newline character.
Example: Phone$ matches Phone only in the line—my Phone.
Matching Any Alphanumeric Character Including the Underscore:
\w instructs QuickTest to match any alphanumeric character and the underscore (A-Z, a-z, 0-9, _).
Example:
\w* causes QuickTest to match zero or more occurrences of the alphanumeric characters—A-Z, a-z, 0-9, and the underscore (_). It matches xyz, p8aj, or 1_uLeu_4.
\w{3} causes QuickTest to match 3 occurrences of the alphanumeric characters A-Z, a-z, 0-9, and the underscore (_). It matches xy4, c7_, or p_n.
Matching Any Non-AlphaNumeric Character
\W instructs QuickTest to match any character other than alphanumeric characters and underscores.
Example: \W matches &, *, ^, %, $, and #.
Combining Regular Expression Operators:
You can combine regular expression operators in a single expression to achieve the exact search criteria you need.
Example: start.* matches start, started, starting, starter, etc.
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