Get Difference value from dataset

Hi , I have a dataset with below mentioned columns

|t_stamp|running|starting|stop|stopping|
|---|---|---|---|---|
|12:00:00 AM|2026686.859|0|604281.2019|0|
|12:04:48 AM|2027128.76|0|604414.1515|0|
|12:09:36 AM|2027569.067|0|604545.232|0|
|12:14:24 AM|2028008.825|0|604675.712|0|
|12:19:12 AM|2028451.945|0|604806.4073|0|
|12:24:00 AM|2028898.808|0|604938.972|0|
|12:28:48 AM|2029341.828|0|605073.8736|0|
|12:33:36 AM|2029784.787|0|605209.7999|0|
|12:38:24 AM|2030227.914|0|605342.7043|0|

Image for your reference

I need to subtract the first row and second row and get the difference and store the value in new dataset with 2nd row timestamp column. Like wise i need to continue for 2nd row with 3rd row and upto last row

how to do this? can anyone please help me out

The use of PyDataSets makes it easier.

sampleHeaders = ['t_stamp','running','starting','stop','stopping']

sampleData = [['12:00:00 AM', 2026686.859, 0, 604281.2019,0],
        ['12:04:48 AM', 2027128.760, 0, 604414.1515,0],
        ['12:09:36 AM', 2027569.067, 0, 604545.232, 0],
        ['12:14:24 AM', 2028008.825, 0, 604675.712, 0],
        ['12:19:12 AM', 2028451.945, 0, 604806.4073, 0],
        ['12:24:00 AM', 2028898.808, 0, 604938.972, 0],
        ['12:28:48 AM', 2029341.828, 0, 605073.8736, 0],
        ['12:33:36 AM', 2029784.787, 0, 605209.7999, 0],
        ['12:38:24 AM', 2030227.914, 0, 605342.7043, 0],
       ]

sampleDataset = system.dataset.toDataSet(sampleHeaders, sampleData)

############################################################################

# PyDataSets lets us easily slice and iterate in a pythonic way.
dataIn = system.dataset.toPyDataSet(sampleDataset)

# Initialize values for creating the output dataset
colNames = list(dataIn.getColumnNames())
data = []

# zip() lets us iterate over multiple objects at the same time. 
# We just happen to use the same PyDataSet starting at the next row.
for prevRow, row in zip(dataIn, dataIn[1:]):
	newRow = [row['t_stamp']]
	# iterate over the remaining columns to get differences.
	for col in colNames[1:]:
		newRow.append(row[col] - prevRow[col])
	data.append(newRow)

dataOut = system.dataset.toDataSet(colNames, data)

dataIn and dataOut:

row | t_stamp     | running     | starting | stop        | stopping
-------------------------------------------------------------------
0   | 12:00:00 AM | 2026686.859 | 0        | 604281.2019 | 0       
1   | 12:04:48 AM | 2027128.76  | 0        | 604414.1515 | 0       
2   | 12:09:36 AM | 2027569.067 | 0        | 604545.232  | 0       
3   | 12:14:24 AM | 2028008.825 | 0        | 604675.712  | 0       
4   | 12:19:12 AM | 2028451.945 | 0        | 604806.4073 | 0       
5   | 12:24:00 AM | 2028898.808 | 0        | 604938.972  | 0       
6   | 12:28:48 AM | 2029341.828 | 0        | 605073.8736 | 0       
7   | 12:33:36 AM | 2029784.787 | 0        | 605209.7999 | 0       
8   | 12:38:24 AM | 2030227.914 | 0        | 605342.7043 | 0       

row | t_stamp     | running | starting | stop     | stopping
------------------------------------------------------------
0   | 12:04:48 AM | 441.901 | 0        | 132.9496 | 0       
1   | 12:09:36 AM | 440.307 | 0        | 131.0805 | 0       
2   | 12:14:24 AM | 439.758 | 0        | 130.48   | 0       
3   | 12:19:12 AM | 443.12  | 0        | 130.6953 | 0       
4   | 12:24:00 AM | 446.863 | 0        | 132.5647 | 0       
5   | 12:28:48 AM | 443.02  | 0        | 134.9016 | 0       
6   | 12:33:36 AM | 442.959 | 0        | 135.9263 | 0       
7   | 12:38:24 AM | 443.127 | 0        | 132.9044 | 0  
2 Likes

One issue i am using system.tag.queryTagHistory to get the data from database

but for same minute i am getting many rows for different seconds.

I want only one row data for the same minute and do the difference calucaltion

Is there any possibility to handle that in your script?

Post some sample data (CSV is fine) and I'll see what can be done.

Thanks i have attached it
sampleData.csv (10.9 KB)

When you use Excel to save your csv, please format the t_stamp column to have the date. Saves me having to add them...

dataIn = system.dataset.toPyDataSet(sampleData)
colNames = list(dataIn.getColumnNames())

# Sort the items into a dictionary. Key keys are the t_stamps truncated to the minute
dataDict = {}
for row in dataIn:
	# Get the timestamp value and set the seconds to 0
	t_stamp = row['t_stamp']
	t_stamp.setSeconds(0)
	
	# Check if the t_stamp exists. 
	if t_stamp not in dataDict.keys():
		# Make an entry if it doesn't
		dataDict[t_stamp] = {}
		# In the nested dictionary, add the column name and it's value-as-a-list
		for col in colNames[1:]: 
			dataDict[t_stamp][col] = [row[col]]
	else:
		# Otherwise, append the column values into their respective lists.
		for col in colNames[1:]:
			dataDict[t_stamp][col].append(row[col])

# Construct dataset
data = []
t_stampList = sorted(dataDict.keys())
for prevT_stamp, t_stamp in zip(t_stampList, t_stampList[1:]):
	newRow = [t_stamp]
	for col in colNames[1:]:
		newRow.append(max(dataDict[t_stamp][col]) - max(dataDict[prevT_stamp][col]))
	data.append(newRow)	

dataOut = system.dataset.toDataSet(colNames, data)
row | t_stamp                      | Running | starting | stop     | stopping
-----------------------------------------------------------------------------
0   | Wed Jan 25 18:19:00 EST 2023 | 123.5   | 0        | 548.4028 | 0       
1   | Wed Jan 25 18:20:00 EST 2023 | 124.25  | 0        | 207.2763 | 0       
2   | Wed Jan 25 18:21:00 EST 2023 | 124.25  | 0        | 0.0      | 0       
3   | Wed Jan 25 18:22:00 EST 2023 | 124.25  | 0        | 0.0      | 0       
4   | Wed Jan 25 18:23:00 EST 2023 | 124.75  | 0        | 0.0      | 0       
5   | Wed Jan 25 18:24:00 EST 2023 | 125.0   | 0        | 0.0      | 0       
6   | Wed Jan 25 18:25:00 EST 2023 | 124.5   | 0        | 0.0      | 0       
7   | Wed Jan 25 18:26:00 EST 2023 | 124.0   | 0        | 0.0      | 0       
8   | Wed Jan 25 18:27:00 EST 2023 | 123.0   | 0        | 0.0      | 0       
9   | Wed Jan 25 18:28:00 EST 2023 | 77.75   | 0        | 0.0      | 0  
1 Like

Hi @JordanCClark

I have tested your code but i am getting wrong output. I don't know where i am making mistake (for same minutes i am getting difference value and its creating dataset)

I have attached project file also for your reference. can you please correct me where i am doing wrong

test_data.zip (29.0 KB)

Can you clarify this, maybe with an example ?

can you please check my test project i have uploaded.

there will be example dataset will be there

if i use system.tag.queryhistory its returning same minutes many rows with different seconds difference.
But i want to subtract one minute row with another minute row and get the difference value and store it in new dataset
like this

row | t_stamp     | running | starting | stop     | stopping
------------------------------------------------------------
0   | 12:04:48 AM | 441.901 | 0        | 132.9496 | 0       
1   | 12:09:36 AM | 440.307 | 0        | 131.0805 | 0       
2   | 12:14:24 AM | 439.758 | 0        | 130.48   | 0       
3   | 12:19:12 AM | 443.12  | 0        | 130.6953 | 0       
4   | 12:24:00 AM | 446.863 | 0        | 132.5647 | 0       
5   | 12:28:48 AM | 443.02  | 0        | 134.9016 | 0       
6   | 12:33:36 AM | 442.959 | 0        | 135.9263 | 0       
7   | 12:38:24 AM | 443.127 | 0        | 132.9044 | 0

I can't, I don't have access to an ignition installation at the moment.

Victor is on the right track methinks; however, I'll be held up in meetings and such for most of my day.