---
title: "Exporting and Importing a CSV"
---

# Exporting and Importing a CSV

> A CSV (comma separated values) file, is one of the most simple structured formats used for exporting and importing datasets. It is a convenient and flexible way to edit and share data across applications. Ignition has a built-in function to convert a dataset to CSV data called [system.dataset.toCSV](appendix\scripting-functions\system-dataset\system-dataset-toCSV.md). You can even convert the contents of a CSV to a script and move it to an Ignition component, such as a Power Table.

This section contains examples for exporting and importing data to a CSV as well as converting the contents of a CSV to a script.

:::note
The examples on this page make use of Vision components, and run in the Vision Client scope.
:::

## Exporting Data to a CSV

You can export a dataset from a query or table to a CSV file.

1. Identify the dataset that you want to export to a CSV file. In this case, we can generate some data on a Power Table and export that data. Drag a **Power Table** component on to your window and toggle its **TestData** property to generate some data.

    ![](testdata.png)

2. Drag a **Button** component on the window, and double click on the Button to open the **Component Scripting** window.
3. Next, let's add our script on the Button component's actionPerformed event. Select the **actionPerformed** event, and click on the **Script Editor** tab.
4. Copy the contents from one of the examples below, and paste the contents to the **Script Editor**. Notice the [system.dataset.toCSV](appendix\scripting-functions\system-dataset\system-dataset-toCSV.md) scripting function is used in the first example to export the dataset to a CSV file:

    ```python title="Python - Hard Coded Filepath"
    # Create a variable that references our Power Table. You could modify this part
    # of the example to point to a different component in the window.
    component = event.source.parent.getComponent('Power Table')
    
    # Use system.dataset.toCSV to turn the dataset into a CSV string
    csv = system.dataset.toCSV(component.data)
    
    # Write to local file system. Note the "r" character right before the directory path.
    # This denotes a raw string literal, meaning we ignore escape sequences (like the "/")
    system.file.writeFile(r"C:\myExports\myExport.csv", csv)
    ```

    ![](actionperformed.png)

5. Instead of hardcoding the path as we did in the above example, we could ask the user to select a directory on the local system with [system.file.saveFile](appendix\scripting-functions\system-file\system-file-saveFile.md):

    ```python title="Python - User Selected Directory"
    # Create a variable that references our Power Table. You could modify this part
    # of the example to point to a different component in the window.
    component = event.source.parent.getComponent('Power Table')
    
    # Use system.dataset.toCSV to turn the dataset into a CSV string.
    csv = system.dataset.toCSV(component.data)
    
    # Use system.file.saveFile to have the user find a directory to write to.
    filePath = system.file.saveFile("myExport.csv", "csv", "Comma Separated Values")
    
    # We can check the value of filePath to make sure the user picked a path before
    # attempting to write.
    if filePath:
        system.file.writeFile(filePath, csv)
    ```

To test your scripts, put the Designer in **Preview Mode**, and press the **Button**. Open your **myExport.csv** file and check your data.

    ![](myexport.png)

## Importing Data from a CSV

There are several ways to import data from a CSV file. First, we could use [system.file.readFileAsString](appendix\scripting-functions\system-file\system-file-readFileAsString.md) to read the entire file as a string. Note, that this will read the file as is, meaning  `\n` can be used to denote new lines.

```python title="Python - Using system.file.readFileAsString()"
# Ask the user to find the CSV in the local file system.
path = system.file.openFile("csv")
 
# Use readFileAsString to read the contents of the file as a string.
# This string will be the parameter we pass to fromCSV below
stringData = system.file.readFileAsString(path)
 
# Split stringData into a List of strings, delimited by the new line character
stringData = stringData.split("\n")
 
# Iterate through the list, and do something with each line
for i in range(len(stringData)):
     
    # We're printing the row here, but you could do something more useful with the data.
    print stringData[i]
```

Alternatively, Python's CSV Library could be use to read in the contents of a CSV. In some cases, this is the easier approach, as the reader object is ready to be iterated over. Note, that this approach does read in each row as a List of strings:

```python title="Python - Using csv.reader()"
# Import Python's built-in csv library
import csv
 
# Ask the user to find the CSV in the local file system.
path = system.file.openFile("csv")
 
# Create a reader object that will iterate over the lines of a CSV.
# We're using Python's built-in open() function to open the file.
file = open(path)
csvData = csv.reader(file)
 
# Iterate through the reader object, and do something with each line
for row in csvData:
     
    # We're printing the row here, but you could do something more useful with the data.
    print row
 
# Close the file once we're done with it
file.close()
```

## Converting the Data into a Dataset

Once you've read in the contents of a CSV into a script, you may wish to move it elsewhere. It is not uncommon to move the data to a **Power Table**, or other components on the screen. The main difficulty with this is converting the CSV data into a dataset so that it fits into the **Power Table** component's **Data** property. We have a couple of approaches listed below.

### Calling the system.dataset.fromCSV Function

The [system.dataset.fromCSV](appendix\scripting-functions\system-dataset\system-dataset-fromCSV.md) function can take a string and convert it to a dataset. Note, that the function expects a very specific format:

```python title="CSV File Content"
#NAMES
Col 1,Col 2,Col 3
#TYPES
I,str,D
#ROWS,6
44,Test Row 2,1.8713151369491254
86,Test Row 3,97.4913421614675
0,Test Row 8,20.39722542161364
25,Test Row 4,20.39722542444222
33,Test Row 5,20.39722542232323
62,Test Row 6,20.39722542111999
```

#### Example

1. Create a Text file on your local system named "**example.csv**."
2. Open the Text file, copy the contents of the "**CSV file Content**" box above, and paste the contents to the file. Save the changes to the **example.csv** file.

    ![](example-notepad.png)

3. Let's move the contents of a CSV file to a Power Table.  Add a **Power Table** and a **Button** component to your window.  Double click on the **Button** component, and paste the following code into the **Script Editor** of the **actionPerformed** event:

    ```python title="Python - Using system.dataset.fromCSV()"
    # Ask the user to find the CSV in the local file system.
    path = system.file.openFile("csv")
    
    # Use readFileAsString to read the contents of the file as a string.
    stringData = system.file.readFileAsString(path)
    
    # Convert the string into a dataset
    data = system.dataset.fromCSV(stringData)
    
    # Pass the dataset to the data property on the Power Table.
    event.source.parent.getComponent('Power Table').data = data
    ```

    ![](fromcsv.png)

4. To execute your script, put the Designer into **Preview Mode**, and press the **Button**. A window will open for you for you to navigate and choose your CSV file, then click Open.

    ![](export-import.png)

Your data will be displayed in the Power Table as shown below.

    ![](power-table.png)

### Calling the csv.reader Function
As mentioned, system.dataset.fromCSV() requires a specific format, which may not match the format of your file. In this case, we can use Python's CSV Library to parse the file and convert it to a dataset.

```python title="CSV File Content"
Col 1,Col 2,Col 3
44,Test Row 2,1.8713151369491254
86,Test Row 3,97.4913421614675
0,Test Row 8,20.39722542161364
25,Test Row 4,20.39722542444222
33,Test Row 5,20.39722542232323
62,Test Row 6,20.39722542111999
```

Here is the code to import the above CSV data.

```python title="Python - Using Python's csv Library"
# Import Python's built-in csv library.
import csv
 
# Ask the user to find the CSV in the local file system.
path = system.file.openFile("csv")
 
# Create a reader object that will iterate over the lines of a CSV.
# We're using Python's built-in open() function to open the file.
file = open(path)
csvData = csv.reader(file)
 
# Create a List of strings to use as a header for the dataset. Note that the number
# of headers must match the number of columns in the CSV, otherwise an error will occur.
# The simplest approach would be to use next() to read the first line in the file, and
# store that at the header.
header = csvData.next()
 
# Create a dataset with the header and the rest of our CSV.
dataset = system.dataset.toDataSet(header ,list(csvData))
 
# Store it into the table.
event.source.parent.getComponent('Power Table').data = dataset
 
# Close the file
file.close()
```