EasyChart: Working with Datasets (Python)


Objective: To add Tag Pens to Easy Chart through scripting.

EasyChart seems to use DataSets to store the Tag Pens that are displayed on the chart. The DataSet includes a number of columns that store the configuration of the Tag being charted (i.e. Name, Tag_Path, Color…).

Question: How do you add a new row through event scripts to this DataSet to add a new Tag Pen to the EasyChart?



Use the system.dataset.addRow() function.




Thanks for the response.

I have used this method, but it increasingly got more complicated as I tried to implement. Building a well formed and type specific row to pass into the dataset does not seem easy (unless you hardcode which is painful and not automated), so I thought there must be a better way. Is there an easy method for creating the row of data (with correct type specific data) that I am missing?

BTW: I did try extracting an existing row from the dataset one element at a time (using the getValueAt()) to see if I could automatically reconstruct a valid row to pass into the dataset,but I ran into issues with coercion (datatyping) as I tried to create the row as a string and feed this back into the dataset.




Maybe you should paste in the code you have tried to use. It is easy for me to construct rows of data for a dataset.

Maybe you can show me how it can be complicated and difficult and then I can show you how to make it easy. I don’t know where or how you are getting your data that you need to add to the dataset so I can’t show you how to prepare the data and add the row.



OK. It’s not pretty, but here is what I have tried so far. This was my last attempt at building the row string correctly.

#Display Event properties for testing purposes
print "Button code: " , event.button, " Click Count: ", event.clickCount

#Work with DataSets to get Easy Chart Tag Pens
tagPenDataSet = event.source.parent.getComponent(“Easy Chart”).tagPens
print "Row Count = “, tagPenDataSet.rowCount, " Column Count = “, tagPenDataSet.columnCount,”\n”,
“Original Data Set : \n”,event.source.displayRows(tagPenDataSet) , “\n”

#Build Easy Chart Dataset Row from scratch in Dictionary format (there is no Row Copy method for Datasets)
easyChartRow = “”
headerTypes = [“str”,“str”,“str”,“str”,“I”,“B”,“clr”,“str”,“I”,“F”,“I”,“B”,“str”,“B”,“B”,“B”,“B”,“I”,“B”]
for column in range(tagPenDataSet.columnCount):
if column == 0:
easyChartRow = “{’” + tagPenDataSet.getColumnName(column) + "’ : "
if headerTypes[column] == “str” or headerTypes[column] == “clr” :
easyChartRow = easyChartRow + “’” + str(tagPenDataSet.getValueAt(0, column)) + “’”
print column, " " ,easyChartRow
easyChartRow = easyChartRow + str(tagPenDataSet.getValueAt(0, column))
print column, " " ,easyChartRow
if headerTypes[column] == “str” or headerTypes[column] == “clr”:
easyChartRow = easyChartRow + “,’” + tagPenDataSet.getColumnName(column) + "’ : " + “’” + str(tagPenDataSet.getValueAt(0, column)) + “’”
print column, " " ,easyChartRow
easyChartRow = easyChartRow + “,’” + tagPenDataSet.getColumnName(column) + "’ : " + str(tagPenDataSet.getValueAt(0, column))
print column, " " ,easyChartRow
easyChartRow = easyChartRow + “}”

print easyChartRow,"\n\n***************************\n\n"

tagPenDataSet = system.dataset.addRow(tagPenDataSet,easyChartRow)

event.source.parent.getComponent(“Easy Chart”).tagPens = tagPenDataSet

Let me know if you have any tricks that can help? I apologies for the poor coding in advance. I am a beginner at best. Thanks in advance.



Hi Chris,
I see that you are attempting to create the new row as a string that looks like a dictionary. The addRow() function needs a python list, in the same order as the existing columns. The following routine will duplicate a specified row and add it to the dataset, which you can then assign to the target property:

def duplicateRow(dataset, rownum): newRow = [dataset.getValueAt(rownum, colnum) for colnum in range(dataset.columnCount)] return system.dataset.addRow(dataset, newRow)
Note the use of [] to make a python list, not a string. This form is called a List Comprehension in the python documentation.
Generally, you’ll want to open-code this kind of manipulation, so you can customize the values in newRow before you add it to the dataset.



Okay, you want to copy a row from a dataset and then add that row to the dataset. Here’s my implementation:

chart = event.source.parent.getComponent("Easy Chart")
tagPenDataSet = system.dataset.toPyDataSet(chart.tagPens)
chart.tagPens = system.dataset.addRow(chart.tagPens,list(tagPenDataSet[0]))

Here’s what happens:

  1. We get the chart.

  2. We convert the Dataset into a PyDataSet. This is done so we can easily access individual rows of the Dataset with a row index like tagPenDataSet[0], tagPenDataSet[1] etc.

  3. We convert the first row into a Python list with the “list” function and use the system.dataset.addRow function to add the row to the dataset.




Thanks everyone, I will give this a shot. Much appreciated.



This is the closest topic and answer thread I have found to what I’m looking for. I’m trying to access the start and end dates on the Easy Chart from python. I have not found any reference to support this programmatic interface.

Thanks for any help,



Is there a way to get the start and end timestamps for the chart, in python?



working code below (Ignition 7.9.8):

code triggered from button in the same Window as EasyChart

eChart = event.source.parent.getComponent(“Easy Chart”)

start_ts = eChart.getZoomedStartDate()
end_ts = eChart.getZoomedEndDate()

strMessage = "Start TS: " + str(start_ts) + “\n” + "End TS: " + str(end_ts)