# Filter CSV Files

> By using this workflow, you can automatically read a `.csv` file, write in the `.csv` files and also append data from one `.csv` file to another `.csv` file.

By using this workflow, you can automatically read a `.csv` file, write in the `.csv` files and also append data from one `.csv` file to another `.csv` file.

This example illustrates how to create an automation process that uses the [Write CSV](https://docs.uipath.com/activities/other/latest/productivity/write-csv-file),[Read CSV](https://docs.uipath.com/activities/other/latest/productivity/read-csv-file) and [Append To CSV](https://docs.uipath.com/activities/other/latest/productivity/append-csv-file) activities. You can find these activities in the **UiPath.Excel.Activities** package.

To exemplify how to use these activities, we have created a sequence that includes a **Write CSV**, **Read CSV** and an **Append To CSV** activity.

This is how the automation process can be built:

1. Open Studio and create a new **Process**.
2. Drag a **Sequence** from the Activities panel to the **Workflow Designer**.
:::note
Add your `.csv` file to the project directory in order to be able to run the entire process from the same place.
:::
3. Drag a **Read CSV** from the Activities panel in the previously created Sequence.
   * In the Properties panel, add the full path of the file you want to read the data from to the **FilePath** property.
   * Select the **IncludeColumnNames** check box. This way, when running the process, the first row in the `.csv` file is considered to contain the column names.
   * Create a new `DataTable` variable called **transactionTable**.
   * In the **Properties** panel, add the newly created variable to the **DataTable** property field.
4. Drag a **Build Data Table** activity from the Activities panel and place it below the **Read CSV** activity.
   * Create a new `DataTable` variable called **transactionsFiltered**.
   * In the Properties panel, add the **transactionsFiltered** variable to the **DataTable** property field.
5. Add another **Build Data Table** activity from the Activities panel and place it below the previous one.
   * Create a new `DataTable` variable called **totalTable**.
   * In the Properties panel, add the **totalTable** variable to the **DataTable** property field.
6. Drag a **For Each Row** activity below the **Build Data Table** activities.
   * In the **Properties** panel, add the **transactionTable** variable to the **DataTable** property field.
7. Drag a **Write CSV** activity under the **For Each Row** activity.
   * In the Properties panel, add the full path of the file in the **FilePath** property. In this case the path can be set as `"TransactionsFiltered.csv"`.
   * In the **Properties** panel, add the **transactionsFiltered** variable to the **DataTable** property field.
   * Make sure to select the **AddHeaders** check box. By doing so, you add the column names from the DataTable to the output `.csv` file.
8. Add a **Read CSV** activity to the **Workflow Designer** and place it under the **Write CSV** activity.
   * In the Properties panel, add the full path of the file you want to read the data from, to the **FilePath** property. In this case you can write as a path `"TransactionsFiltered.csv"`.
   * Check the **IncludeColumnNames** option. This considers the first row of the `.csv` file to have the column names.
   * Add the **transactionsFiltered** variable in the **DataTable** output field, from the Properties panel.
9. Add a **While** activity below the **Read CSV**.
   * In the Properties panel, set the **Condition** field to `counter<transactionsFiltered.Rows.Count`.
   * Drag a **Sequence** activity in the body of the **While** activity.
   * Inside the **Sequence** activity, add three **Get Row Item** activities.
   * All **Get Row Item** activities should have in the **Row** field the following text `transactionsFiltered.Rows(counter)`.
10. Drag four **Assign** activities right after the **Get Row Item** activities.
    * Create four new `Double` variables **sumCashIn**, **sumOnUsCheck**, **sumNotOnUsCheck** and an `Int32` variable named **counter**.
    * In the first **Assign** activity add in the **To** field the **sumCashIn** variable and in the **Value** field add `sumCashIn+cashIn`.
    * In the second **Assign** activity add in the **To** field the **sumOnUsCheck** variable and in the **Value** field add `sumOnUsCheck+onUsCheck`.
    * In the third **Assign** activity add in the **To** field the **sumNotOnUsCheck** variable and in the **Value** field add `sumNotOnUsCheck+notOnUsCheck`.
    * In the fourth **Assign** activity add in the **To** field the **counter** variable and in the **Value** field add `counter + 1`.
11. Add a **Add Data Row** activity under the **While** activity.
    * In the **Properties** panel, add `{sumCashIn,sumOnUsCheck,sumNotOnUsCheck}` in the **ArrayRow** field and the `totalTable` variable in the **DataTable** field.
12. Drag an **Append To CSV** activity below the **Add Data Row** activity.
    * Add the path of the file. In this case it is `"TransactionsFiltered.csv"`.
    * In the **DataTable** field add the `totalTable` variable.
13. Run the process. Once the automation is completed, you have two `.csv` files in your project, the initial one and a newly created one that includes all the filtered data.

[Download example](https://docexamples.uipath.com/examples/Activities/Filter%20CSV%20files%20example.zip)