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====LESSON 7: Creating a new column and retrieving a data column from tables====
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  * To create a new column in a given table we must open all the files that will be used to retrieve data from. Click on the Input/Output tab from the library window and grab three [[Load Lookup Table]] Functors and one [[Load Table]] placing them on the sketch. Open the [[Load Lookup Table]] functors and load the files ''1999_production_value.csv'', ''1999_harvested_area.csv'' and ''1999_production.csv'' from the folder ''Guidebook_Dinamica_5\Database\Tables\''. Next, open [[Load Table]] and load ''IBGE_crop_information_uptated.csv''.
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  * Now we can create a new column merge between the ''1999_harvested_area.csv'' and ''1999_production.csv'' files. On the Input/Output tab, grab an [[Add Table Column]] and place it on the sketch. Connect the [[Load Lookup Table]] which contains the file ''1999_harvested_area.csv'' to [[Add Table Column]], selecting __Table__ as an input port. On the Functor Editor window, write a name for the created column (e.g. “production_value”). 
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<note important>
The position where the new column is inserted determines whether the new column is a key or data column.
</note>
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  * Connect the [[Load Lookup Table]] which contains the file ''1999_production.csv'' to [[Add Table Column]], the __Column Values__ port will be automatically assigned as an input port.
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  * Add another [[Add Table Column]] to the sketch, assign the output of the previous [[Add Table Column]] to the __Table__ input port of the recently added functor. Connect the [[Load Lookup Table]] with ''1999_production_value.csv'' to the new [[Add Table Column]]. In the Functor Editor window, choose a name for the created column (e.g. "production"). 
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  * Add a [[Set Table By Key]] to the sketch, assign the output of [[Add Table Column]] to the __Subtable__ input port of [[Set Table By Key]] and the [[Load Table]] with ''IBGE_crop_information_uptated.csv'' to the __Table__ port. In the Functor Editor window, enter ''1999'' as the key identifying the sub-table that will be updated or inserted. Additionally, toggle the __Ignore Column Names__ flag in the Functor Editor Window.
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  * To save the result to a file, place a [[Save Table]] on the sketch, browse to ''\Guidebook_Dinamica_5\Models\add_table_column_set_table_by_key'' and write the file name (e.g. ''IBGE_crop_information_complete''). 
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  * Click on the layout tool Execute Layout. Your final model should be similar to the one below: 
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  * Save and run the model. Select the [[Save Table]] functor and click on the eye button to open the resulting table.
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Using the table generated previously, we would like to demonstrate how to retrieve a data column from it.
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  * Grab a [[Load Table]], placing it on the sketch. Double click it and open the file generated in last step (e.g. ''IBGE_crop_information_complete.csv'').
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  * To retrieve a data column corresponding to the harvested area, we will use [[Get Table Column]]. Connect the [[Load Table]] to [[Get Table Column]]. In the input __Column Index or Name__ of the Functor Editor window, insert the index of the column to be retrieved (“3” or “harvested area”).
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  * Now, we can retrieve the harvested area per crop corresponding to the year of 2004.  For this, grab a [[Get Table from Key]] and place it on the sketch. Connect [[Get Table Column]] to [[Get Table from Key]]. In the input __Keys__ of the Functor Editor window, insert the year you want to retrieve the harvested area per crop (in this example, “2004”).
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  * Grab a [[Save Table]] and place it on the sketch. Connect [[Get Table From Key]] and [[Save Table]]. The final model should have the following structure: 
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  * To save the result to a file, edit [[Save Table]], browse to ''\Guidebook_Dinamica_5\Models\add_table_column_set_table_by_key'' and write the file name (e.g. IBGE_crop_information_update).
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  * Save and run the model. To see the resulting table, click on eye button of [[Save Table]]. This functor output is a table that looks like this:
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==== Congratulations, you have successfully completed this lesson! ====
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☞[[:lesson_8 | Next Lesson]]
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☞[[:guidebook_start| Back to Guidebook Start]]