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Document Understanding Activities
Last updated Apr 10, 2024

RegEx Based Extractor


Enables you to create and use a custom Regular Based Expression to extract information from a document. This activity can be used only together with the Data Extraction Scope activity.


Note: This activity cannot work with set or boolean fields.
  • DisplayName - The display name of the activity.
  • Configuration - Specifies the configuration value for the extractor as a JSON escaped string. Use the extractor wizard to generate the configuration. You can keep the configuration in the Properties panel, as a string, or you can define it by using the wizard and bind it to a variable. It is advisable to edit the Configuration field by using the wizard and not the Properties panel.
  • Timeout - Specifies the timeout value for any Regex search, in milliseconds. A timeout of 0, or negative, is interpreted as infinite. The default value is 2000.
  • UseVisualAlignment - If selected, the regular expressions are applied to a text version generated based on visual word alignments (a visual word alignment includes words separated by a single space character, lines separated by a single newline character, and pages separated by two lines characters). The default value is False. This option can be used for complex layouts where it is easier for users to write regular expressions based on how words are visually organized on lines, ignoring any sentence, paragraph, or layout group otherwise identified in the document.
  • Private - If selected, the values of variables and arguments are no longer logged at Verbose level.

Using the Configure Regular Expression Wizard

  1. Add a RegEx Based Extractor activity to your workflow, within a Data Extraction Scope activity.
  2. Configure your regular expressions by clicking on the Configure Expressions button.

    • The Wizard window opens.

  3. Expand a document type entry in order to see all defined fields, and to start configuring your regular expressions. Document types and their respective fields are automatically read from the project's Taxonomy. The Regex configuration option is available for every field in the taxonomy.

    • expanded document type showing a single regular field:

    • Expanded document type and table field, showing configuration options for a table:

      For a simple field, only a single regular expression can be defined using the RegEx wizard that opens when you click the "Edit" option next to that field.

      For a table field, there are multiple settings and options available for configuration:

    • The Table Value RegEx can be used for capturing an entire table area. If no value is added on the Table field line, the entire text content of the document is considered onward for table processing.
    • The Rows Value RegEx can be used for capturing an entire row from a given table capture. If no value is added on the Rows field line, the table area is split by end-of-line. Each captured value is considered from this point forward as a row on which the column extraction is to be applied.
    • The Column Value RegEx can be used for capturing the value of a particular column, from each captured row.

      Scenarios of using the Table, Rows and Column Regex:

    • If you leave the Table RegEx and the Rows RegEx fields empty, all lines in the text version of the document are used to apply the Column Level Regexes for cell value identification.
    • If you define a RegEx to capture the table area, but leave the Rows RegEx empty, all lines in the table capture are individually processed using each Column RegEx to capture the cell values.
    • If you leave the Table RegEx empty but define a Rows RegEx, then all text captured with the Rows RegEx is used and the Column RegExes are applied to capture cell values for each row.
    • If you fill in both Table and Rows RegEx, the activity applies the Table RegEx to identify the table string, then apply the Rows RegEx to identify each line, followed by the Column Level RegEx for capturing cell values.
  4. Add your Regular Expression in the Expression field.

    Note: You have the option of either writing the whole RegEx in the Expression field or to build it by using the Edit button.
    Important: For any of the regular expressions you define, make sure you have at least one capture group! Only the captured parts of an expression are used for value reporting.
  5. Click on the drop-down list from the Regex Options column. You can set Regex Options from this multi-select option.

  6. There are multiple options you can choose from:

    • CultureInvariant - Specifies that the linguistic cultural differences are ignored.
    • ECMAScript - Enables ECMA Script compliant behavior for the expression. This value can be used only in conjunction with the IgnoreCase and Multiline options.
    • ExplicitCapture - Specifies that the only valid captures are the ones of groups that are explicitly named or numbered and are defined as (?<name> subexpression). Any unnamed parentheses are to be ignored.
    • IgnoreCase - Specifies that the search is not case sensitive.
    • IgnorePatternWhitespace - Eliminates the unescaped white space from the defined pattern and enables the comments marked with #. This option does not apply to character classes, numeric quantifiers, or tokens marking the beginning of an individual RegEx language element.
    • Singleline - Specifies that the search is initiated in a single line. The dot (.) matches all characters, including the exception \n.
    • Multiline - Specifies that the search is initiated in multiple lines. For this option, the special characters ^ and $ match the beginning and the ending of any line.
    • RightToLeft - Specifies that the search is performed from right to left.

      Note: More information about the Regular Expression Options can be found here.

The Regex Editor Wizard

  1. Click on the Edit button to edit the options of that field and the format of the regular expression.

  2. Add text in the Test Text field for testing the search criteria you choose against the text that you want to apply RegEx on.

  3. Select one of the RegEx formula types from the drop-down list. This sets the Regular expression to match one of the following characteristics:

    • Literal - Matches the exact characters specified by you. This option is case sensitive.
    • Digit - Matches a digit.
    • One of - Matches a single character present in the set.
    • Not one of - Matches a single character not present in the set.
    • Anything - Matches any character, except for \n.
    • Any word character - Matches any letters and numbers.
    • Whitespace - Matches one white space.
    • Starts with - Initiates the search where the line starts.
    • Ends with - Initiates the search where the line ends.
    • Advanced - Requires a custom expression.
    • Email - Matches an email address.
    • URL - Matches an URL.
    • US date - Matches the US date format.
    • US phone number - Matches the US phone number format.

      Note: More information about the Regular Expressions in .NET can be found here.
  4. Use the Value field for writing the value of the regular expression.
  5. Select a quantifier from the Quantifiers drop-down list.

    • Exactly - Matches the preceding element exactly how many times it is specified. By default, it is set to 1.
    • Any (0 or more) - Matches the preceding element for zero or more times, but as few times as possible.
    • At least one (1 or more) - Matches the preceding element for one or more times.
    • Zero or one - Matches the preceding element for zero or one time but for as few times as possible.
    • Between x and y times - Matches the preceding element between x and y times, where x and y are integers, but as few times as possible.
  6. Use the docs image button for adding an extra RegEx field. Move fields up and down in the hierarchy by using the docs image and docs image buttons. Use the docs image button for deleting the field.
  7. Select the check box for the Capture option if you want to extract that specific field.
  8. The Full Expression field shows the entire expression exactly how it was customized by you.
  9. Select one or multiple options from the Regex Options drop-down list.

  10. Click the Save button once all your configurations are done to exit the Edit mode and then click the Save once again for closing the wizard.
Document Understanding Integration

The RegEx Based Extractor activity is part of the Document Understanding Solutions.

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