Regex syntax

Find the list of basic regex metacharacters and illustrate the basic syntax of regexes by way of example strings.

Ranorex Studio uses the .NET regex engine. It is quite powerful and complex, and explaining all of it would be beyond the scope of this user guide. If you would like in-depth information on it, please refer to Microsoft’s official .NET guide article.

There is a set of characters that are used in regexes as operators. These characters are called metacharacters.

If you don’t want the regex engine to interpret them as metacharacter, e.g. because you want to find one in a string, you need to “escape” them. This means preceding the metacharacter with a backslash, for example, $.

Single-element expressions

[1234567]

• Matches a single character that is contained in the bracket expression, i.e. a number between 1 and 7 here
• Alternative expression: [1-7]

[Max]

• Matches any single letter contained in the bracket expression, i.e. “M”, “a”, or “x”.
• Important: Does not match the word “Max”.

[1-35-8]

• Matches the numbers 1, 2, 3, 5, 6, 7, 8.
• Does not match the number 35.

Multi-element expressions

[1-9][ab]

• Matches any combination of the bracket expressions, i.e. “1a”, “1b”, “2a”, “2b”, …., “9a”, “9b”.

Quantifiers

The quantifier metacharacters ?, +, *, and {} are placed after the characters they should apply to.

[1-9]?

• Matches a string that contains any of the numbers between 1 and 9 either zero or one time.
• (Colou?r) would therefore match both “Colour” and “Color”.

[1-9]+

• Matches any number that consists of one or more numbers between 1 and 9.
• In other words, matches any number greater than 0.

[0-9]{5}

• Matches any five-digit number.

[0-9]{3,}

• Matches any number with at least three digits.

[0-9]{3,5}

• Matches any number with at least three and at most five digits.

Match the beginning of a string

^Image_

• Matches all strings that start with “Image_”

(^Image_)[0-9]{3}

• Matches all strings that start with “Image_” followed by a three-digit number.
• Examples for matched strings: “Image_001”, “Image_999”, “Image_127”, …

(^Image_)[0-9]{3}(.jpg)

• Matches all strings that start with “Image_” followed by a three-digit number and “.jpg”.
• Note that the period character. is escaped with a backslash.

Match end of string

Sample$

• Matches all strings that end in “Sample”.

(Sample[0-9]{3}$)

• Matches all strings that end in “Sample” followed by a three-digit number.

Placeholders

Image.*

• Matches all strings that consist of “Image” followed by any number of other characters.
• . is the placeholder for any character.
• Examples for matched strings: “Image3459834059346237832jkhdsdb”, “Image”, “ImageTheCat”

Match alternatives

((G|g)r(a|e)y)

• Matches the strings “Gray”, “gray”, “Grey”, and “grey”.

Exclude characters

With [^ you can exclude characters.

[^0-9]

• Excludes all numbers. Therefore, matches any string that doesn’t contain any numbers.

You can also use regexes in RanoreXPath expressions. Here are some examples: