{{ transformations:ReorderColumnsWithListAction.png}}
====== REORDER COLUMNS WITH LIST ======
Category: Transform / Advanced\\

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=====Description=====
This action puts the columns of the current table in a custom order, defined by a list of column names in another table.

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=====Use cases=====
  * Order columns according to a list that comes from data, instead of a fixed order set in the action
  * Ensure a particular order of columns before exporting to a file

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=====Action settings=====
^Setting^Description^
|Another table|Select the other table in the project that contains the list of column names.|
|Column with names|Select the column of the other table that contains the column names in the desired order.|
|Columns that are not on the list|Choose what happens to the columns of the current table whose names are not in the list.  Options:  //Preserve position//, //Move all to the left//, or //Move all to the right//. \\ \\ With //Preserve position//, the columns that are not on the list stay where they are, and the listed columns take the remaining positions in list order. See the Example below.|

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=====Remarks=====
A name in the list that doesn't match a column of the current table is ignored.

The action fails if the same name appears in the list more than once, or if a value in the list cannot be used as a column name.

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=====Examples=====

====Example #1====
>Put the "Continent" column first and the "River" column last, using a list in another table.

===Before (source table)===
^River  ^Length (km)  ^Continent  ^
|Nile  |  6650|Africa  |
|Amazon  |  6400|South America  |
|Yangtze  |  6300|Asia  |

===Other table "Column order"===
^Name  ^
|Continent  |
|River  |

===After (result table)===
^Continent  ^Length (km)  ^River  ^
|Africa  |  6650|Nile  |
|South America  |  6400|Amazon  |
|Asia  |  6300|Yangtze  |

"Length (km)" is not on the list, so it keeps its middle position. The two listed columns take the remaining positions, in the order they appear in the list.

===Action parameters:===
>  Another table: Column order
>  Column with names: Name
>  Columns that are not on the list: Preserve position

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=====See also=====
  * [[transformations:reorder|Reorder columns]]
  * [[transformations:lookuprename|Rename columns with lookup]]
  * [[transformations:selectbylookup|Select columns by lookup]]