Differences

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--- transformations:filter [2015/06/12 21:20] – dmitry
+++ transformations:filter [2021/07/19 02:15] – [Examples] craigt
@@ Line 1: / Line 1: @@
-===== Filter by Condition =====
+{{ transformations:ExpressionFilterAction.png}}
+====== FILTER BY CONDITION======
+Category: Transform / Filters\\
-This transformation calculates an [[syntax:start|expression]] for every row (without adding a new column) and keeps only rows where this expression is true. Other rows are removed.
+\\
+=====Description=====
+This action calculates an [[syntax:start|expression]] for every row (without adding a new column) and keeps only rows where this expression is TRUE. All other rows are removed.
-The expression must be a valid condition -- it must return either TRUE or FALSE for any row in the table. If it results in a non-boolean value (i.e. not TRUE or FALSE) for at least one row it will cause a project execution error.
+If no rows satisfy the condition then all rows are removed.\\
-**Examples of conditions**
+The expression must be a valid condition -- it must return either TRUE or FALSE for any row in the table. If it results in a non-boolean value (i.e. not TRUE or FALSE) for at least one row it will cause a project execution error.\\
-  [Amount]=0
+\\
+=====Use cases=====
+Create subsets of a dataset based on values across multiple columns.
+Clean a dataset by removing records that don't meet certain criteria, or evaluate to a certain value. \\
+\\
+=====Action settings=====
+^Setting ^Description ^
+|Expression|Enter an expression that evaluates to a boolean TRUE/FALSE result.  The expression will be applied to each\\ record and remove records that do not meet the criteria (evaluate to FALSE).|
+\\
+=====Remarks=====
+Examples of valid conditions:
+<code>
+[Amount]=0
-  [Length] * [Width] * [Height] <= 1000
+[Length] * [Width] * [Height] <= 1000
-  contains([City], 'York')
+contains([City], 'York')
-  not isempty([Email])
+not isempty([Email])
+</code>
-If no rows satisfy the condition then all rows are removed.
-**Example of transformation**
+\\
+=====Examples=====
+**Example:** Find all rivers that are longer than 6000 km.\\
 **Source table:** The longest rivers in the world
+^River  ^Length (km)  ^Continent  ^
+| Nile  |  6650| Africa  |
+| Amazon  |  6400| South America  |
+| Yangtze  |  6300| Asia  |
+| Mississippi  |  6275| North America  |
+| Yenisei  |  5539| Asia  |
+| Yellow River  |  5464| Asia  |
+| Ob  |  5410| Asia|
+| Paraná  |  4880| South America  |
+\\
+**Action parameters:**
+> Expression: [Length (km)] > 6000
-^  River  ^  Length (km)  ^  Continent  ^
+\\
-| Nile  |  6650  |  Africa  |
+**Result table:**
-| Amazon  |  6400  |  South America  |
+^River  ^Length (km)  ^Continent  ^
-| Yangtze  |  6300  |  Asia  |
+| Nile  |  6650| Africa  |
-| Mississippi  |  6275  |  North America  |
+| Amazon  |  6400| South America  |
-| Yenisei  |  5539  |  Asia  |
+| Yangtze  |  6300| Asia  |
-| Yellow River  |  5464  |  Asia  |
+| Mississippi  |  6275| North America  |
-| Ob  |  5410  |  Asia  |
-| Paraná  |  4880  |  South America  |
-**Objective:** Find all rivers that are longer than 6000 km
-**Transformation parameters:**
-  * Column: Length (km)
-  * Expression: [Length (km)] > 6000
-**Output table:**
-^  River  ^  Length (km)  ^  Continent  ^
+\\
-| Nile  |  6650  |  Africa  |
+====Community examples====
-| Amazon  |  6400  |  South America  |
+  * [[https://community.easymorph.com/t//675/5|Compare two Excel sheets with EasyMorph]] ([[https://community.easymorph.com/uploads/short-url/xQLWtAogCqcMrglyfXLKmrAF7aR.morph|Project]]; Module: //Main//; Group: //Main//; Table: //Result//; Action position: //3//)
-| Yangtze  |  6300  |  Asia  |
+  * [[https://community.easymorph.com/t//1625/4|Create a new table with columns based on row values]] ([[https://community.easymorph.com/uploads/short-url/4oGLUNDHrUfB971H80ciuOAtOTG.morph|Project]]; Module: //Module 1//; Group: //Tab 1//; Table: //Table 1//; Action position: //2//)
-| Mississippi  |  6275  |  North America  |
+  * [[https://community.easymorph.com/t//1649/4|Update existing data in a database table]] ([[https://community.easymorph.com/uploads/short-url/yB6WDyNxKmlLT3bbm6mTr76C4Ri.morph|Project]]; Module: //Main//; Group: //Tab 1//; Table: //Where clause//; Action position: //2//)
+  * [[https://community.easymorph.com/t//1766/1|Load only workbooks with given number of sheets]] ([[https://community.easymorph.com/uploads/short-url/AbWPlfPVBecqgZUBVTYlljwb9NO.morph|Project]]; Module: //Main//; Group: //Tab 1//; Table: //Get file names to load//;\\ Action position: //5//)
+  * [[https://community.easymorph.com/t//2041/6|Join 2 tables with multi criterions equal and not equals in where]] ([[https://community.easymorph.com/uploads/short-url/kNkqMsDYMJjzjiN4C5g8O4g3YlA.morph|Project]]; Module: //Main//; Group: //Tab 1//; Table: //Join//; Action position: //3//)
-=== See also ===
+\\
+=====See also=====
   * [[transformations:selectionfilter|Filter]]
-  * [[syntax:start|Expression syntax]]
+  * [[transformations:searchfilter|Filter by search]]
-  * [[syntax:errorpropagation|Error propagation in expressions]]
+  * [[transformations:filterbytype|Filter by type]]
+  * [[syntax:start|Expressions:  Expression syntax]]