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+{{ transformations:FilterByTypeAction.png}}
+====== FILTER BY TYPE ======
+Category: Transform / Filters\\
+\\
+=====Description=====
+This action filters values depending on their [[syntax:types|data type]]. Filtering can be applied to several columns at once, as well as multiple data types.\\
+\\
+=====Use cases=====
+Filtering by type helps detect data quality issues by ensuring that columns in the exported dataset are strongly typed (i.e. all values in a column are of the same type). This might be required before exporting into a target system with strongly typed fields, such as a relational database or a Tableau data extract.
+The //Filter by type// action is frequently followed by the [[transformations:halt|Halt on condition]] action that stops project execution if filtering returned a non-empty table with values of undesired types.\\
+\\
+=====Action settings=====
+^Setting ^Description ^
+|Filter mode|Select whether to keep or remove values of the types specified.  Options:  //Keep only values of selected type(s)// or\\ //Remove values of the selected types//.|
+|Data types|Select the data types to be filtered by.  Options:  //Text//, //Number//, //Boolean//, //Error//, and //Empty (null)//. |
+|Columns to check|Select whether to check the entire table or specific columns.  Options:  //Entire table// or //Particular columns// (and\\ select the columns check).|
+\\
+=====Remarks=====
+In cases where no values match the search string:
+  * If //Keep only values…// was selected, the result will be an empty dataset.
+  * If //Remove values…// was selected, the result will be the full dataset (no rows removed).
+\\
+=====Examples=====
+**Objective:**  Filter out all non-numberic values in the "Length (km)" column.\\
+**Source table:** The longest rivers in the world
+^River  ^Length (km)  ^Continent  ^
+| Nile  |  6650| Africa  |
+| Amazon  |  6400| South America  |
+| Yangtze  |N/A  | Asia  |
+| Mississippi  |  6275| North America  |
+| Yenisei  |  5539| Asia  |
+| Yellow River  |  5464| Asia  |
+| Ob  |  5410| Asia  |
+| Paraná  |  | South America  |
+\\
+**Action parameters:**
+> Filter mode is "Keep only values of selected type(s)"
+> Data types:  "Number" selected
+> Columns to check; Particiular columns:  "Length (km)"
+\\
+**Result:**
+^River  ^Length (km)  ^Continent  ^
+| Nile  |  6650| Africa  |
+| Amazon  |  6400| South America  |
+| Mississippi  |  6275| North America  |
+| Yenisei  |  5539| Asia  |
+| Yellow River  |  5464| Asia  |
+| Ob  |  5410| Asia  |
+\\
+=====See also=====
+  * [[transformations:selectionfilter|Filter]]
+  * [[transformations:filter|Filter by condition]]
+  * [[transformations:searchfilter|Filter by search]]