# The expression language used in advanced mode

When you create a rule in advanced mode, you must follow the specific syntax of the [Using Data Shaping Expression Language](https://help.qlik.com/talend/en-US/data-shaping-language-reference-guide/8.0/using-data-shaping-expression-language).

As the data quality rules are validation rules, use the expression language to validate the data, not to transform them.

For example: The expression concat(' ',FirstName,LastName) == FullName validates that the full name corresponds to the first name concatenated with the last name with a space as a separator.

The following functions are specific to the data quality rules as a supplement to the expression language:

| Function | Details | Example |
| --- | --- | --- |
| isInMonth(myVar,<br>myMonth) | Type a month or a number from 1 to 12.<br><br>1 =<br>January...12 = December \*<br><br>The supported languages are: English, French, German,<br>Portuguese, and Spanish. \*<br><br>You can also use the English<br>abbreviations: Jan, Feb... \* | isInMonth(myVar,<br>"July")<br>isInMonth(myVar, 7) |
| isInYear(myVar, myYear) | - | isInYear(myVar, 2020) |
| isOfType (myvar,<br>myType) | Type a semantic type or standard type: boolean, date, decimal<br>or integer. | isOfType (myVar,<br>"Integer") |
| isOnDayOfMonth(myVar, myDay) | Type a number from 1 to 31. | isOnDayOfMonth(myVar,<br>18) |
| isOnDayOfWeek(myVar,<br>myDay) | Type a day or a number from 1 to 7.<br><br>1 = Monday...7 = Sunday \*<br><br>The supported languages are: English, French, German,<br>Portuguese, and Spanish. \*<br><br>You can also use the English abbreviations: Mon, Tue... \* | isOnDayOfWeek(myVar,<br>"Tuesday")<br>isOnDayOfWeek(myVar, 2) |
| \* This applies for the rule definition and the dataset. For example:<br><br><ul> <li>You defined the rule using the value												<kbd>Wednesday</kbd>. If the dataset											contains the values <kbd>Mercredi</kbd>,												<kbd>3</kbd> and												<kbd>Wed</kbd>, the value												<kbd>Wednesday</kbd> is considered to be											equal to these three values.</li> <li>You defined the rule using the value												<kbd>Juni</kbd>. If the dataset contains											the value <kbd>June</kbd>, the value												<kbd>Juni</kbd> is considered to be											equal to <kbd>June</kbd>.</li> </ul> |  |  |

These functions are also available in basic mode. For more information, see the [The operators](https://help.qlik.com/talend/en-US/data-stewardship-user-guide/8.0/operators).

Information noteImportant: For security reasons, a few regular expressions cannot be used, especially the backreferences. For more information, see the [RE2/J documentation](https://github.com/google/re2j).