# Custom Tag History Aggregate

**URL:** <https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [January 13, 2025, 8:52am UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791 "2025-01-13T08:52:11Z")\
**Posts on this page:** 18\
**Page:** 1

<div class="post-metadata">

**Author:** ![liam1](https://avatars.discourse-cdn.com/v4/letter/l/e68b1a/32.png) [@liam1](https://forum.inductiveautomation.com/u/liam1)\
**Post date:** [January 13, 2025, 8:52am UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/1 "2025-01-13T08:52:11Z")

</div>

Hi all,

I'm trying to make a custom Tag History Aggregate which will return the min and max value for a period of time but excludes 0's.The reason for this is because the totalizer tag history has erroneous zero values recorded

Here is the code I wrote so far. Can someone point out what I am doing wrong here?

```python
def myMinMax(qval, interpolated, finished, blockContext, queryContext):
	# Initialize min and max values
	current_min = blockContext.getOrDefault('current_min', float(0))
	current_max = blockContext.getOrDefault('current_max', float(0))
	
	# Check if the incoming value is good and not zero
	if qval.quality.isGood() and qval.value != 0:
	    current_min = min(current_min, float(qval.value))
	    current_max = max(current_max, float(qval.value))
	
	# Debugging output
	print("Current Min: {}, Current Max: {}".format(current_min, current_max))
	
	# Store updated min and max in blockContext
	try:
	    blockContext['current_min'] = current_min
	    blockContext['current_max'] = current_max
	except Exception as e:
	    print("Error updating blockContext: {}".format(e))
	
	# If finished is true, return results
	if finished:
	    # If no valid values were found, return None
	    
	    if current_min == 0 or current_max == 0:
	        return None
	    return [current_min, current_max]

```

Here is the stack trace error I'm getting when trying to run it:

```python
Java Traceback:
Traceback (most recent call last):
  File "<input>", line 13, in <module>
	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(GatewayInterface.java:360)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.getResponse(GatewayInterface.java:500)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:292)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:287)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.runTagCalculationQuery(GatewayInterface.java:828)

	at com.inductiveautomation.ignition.client.script.ClientTagUtilities.queryTagCalculationsImpl(ClientTagUtilities.java:349)

	at com.inductiveautomation.ignition.common.script.builtin.AbstractTagUtilities.queryTagCalculations(AbstractTagUtilities.java:808)

	at jdk.internal.reflect.GeneratedMethodAccessor127.invoke(Unknown Source)

	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

	at java.base/java.lang.reflect.Method.invoke(Unknown Source)

com.inductiveautomation.ignition.client.gateway_interface.GatewayException: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Unable to read response from Gateway.

	at org.python.core.Py.JavaError(Py.java:545)

	at org.python.core.Py.JavaError(Py.java:536)

	at org.python.core.PyReflectedFunction. __call__ (PyReflectedFunction.java:192)

	at com.inductiveautomation.ignition.common.script.ScriptManager$ReflectedInstanceFunction. __call__ (ScriptManager.java:553)

	at org.python.core.PyObject. __call__ (PyObject.java:400)

	at org.python.pycode._pyx394.f$0(<input>:20)

	at org.python.pycode._pyx394.call_function(<input>)

	at org.python.core.PyTableCode.call(PyTableCode.java:173)

	at org.python.core.PyCode.call(PyCode.java:18)

	at org.python.core.Py.runCode(Py.java:1703)

	at org.python.core.Py.exec(Py.java:1747)

	at org.python.util.PythonInterpreter.exec(PythonInterpreter.java:277)

	at org.python.util.InteractiveInterpreter.runcode(InteractiveInterpreter.java:130)

	at com.inductiveautomation.ignition.designer.gui.tools.jythonconsole.JythonConsole$ConsoleWorker.doInBackground(JythonConsole.java:628)

	at com.inductiveautomation.ignition.designer.gui.tools.jythonconsole.JythonConsole$ConsoleWorker.doInBackground(JythonConsole.java:616)

	at java.desktop/javax.swing.SwingWorker$1.call(Unknown Source)

	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)

	at java.desktop/javax.swing.SwingWorker.run(Unknown Source)

	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

	at java.base/java.lang.Thread.run(Unknown Source)

Caused by: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Unable to read response from Gateway.

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(GatewayInterface.java:360)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.getResponse(GatewayInterface.java:500)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:292)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:287)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.runTagCalculationQuery(GatewayInterface.java:828)

	at com.inductiveautomation.ignition.client.script.ClientTagUtilities.queryTagCalculationsImpl(ClientTagUtilities.java:349)

	at com.inductiveautomation.ignition.common.script.builtin.AbstractTagUtilities.queryTagCalculations(AbstractTagUtilities.java:808)

	at jdk.internal.reflect.GeneratedMethodAccessor127.invoke(Unknown Source)

	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

	at java.base/java.lang.reflect.Method.invoke(Unknown Source)

	at org.python.core.PyReflectedFunction. __call__ (PyReflectedFunction.java:190)

	... 18 more

Caused by: com.inductiveautomation.ignition.client.gateway_interface.ResponseParser$1: Error reading data element [row=0, column="AD-HOC-PYTHON", type=Long]
java.lang.NumberFormatException: For input string: "299748.8405131454"

	at com.inductiveautomation.ignition.client.gateway_interface.ResponseParser.endElement(ResponseParser.java:290)

	at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)

	at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.getResponse(GatewayInterface.java:498)

	... 27 more

Caused by: java.lang.NumberFormatException: For input string: "299748.8405131454"

	at java.base/java.lang.NumberFormatException.forInputString(Unknown Source)

	at java.base/java.lang.Long.parseLong(Unknown Source)

	at java.base/java.lang.Long.parseLong(Unknown Source)

	at com.inductiveautomation.ignition.common.TypeUtilities.coerceLocaleSafe(TypeUtilities.java:899)

	at com.inductiveautomation.ignition.client.gateway_interface.ResponseParser.endElement(ResponseParser.java:273)

	... 38 more

Traceback (most recent call last):
  File "<input>", line 13, in <module>
	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(GatewayInterface.java:360)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.getResponse(GatewayInterface.java:500)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:292)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:287)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.runTagCalculationQuery(GatewayInterface.java:828)

	at com.inductiveautomation.ignition.client.script.ClientTagUtilities.queryTagCalculationsImpl(ClientTagUtilities.java:349)

	at com.inductiveautomation.ignition.common.script.builtin.AbstractTagUtilities.queryTagCalculations(AbstractTagUtilities.java:808)

	at jdk.internal.reflect.GeneratedMethodAccessor127.invoke(Unknown Source)

	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

	at java.base/java.lang.reflect.Method.invoke(Unknown Source)

com.inductiveautomation.ignition.client.gateway_interface.GatewayException: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Unable to read response from Gateway.

```

Here is how I am calling the aggregation function:

```python
# Get current date
end = system.date.now()

start =system.date.addDays(end, -20) #end.replace(day=1, hour=0, minute=0, second=0, microsecond=0)

query=system.tag.queryTagCalculations(
	paths=['[Canary/default:default]HYPERV-CANARY/Ignition/process/p_auxiliary/chlorine/pressure_transmitters/post_chlorine/totalizer'],
	calculations=['shared.myMinMax'],
	startDate=start,
	returnSize=100,
	ignoreBadQuality=True,
	endDate=end)
print query

```

---

<div class="post-metadata">

**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\
**Post date:** [January 13, 2025, 9:58am UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/2 "2025-01-13T09:58:37Z")

</div>

I don't think I can help, but what is the line  
`print("Current Min: {}, Current Max: {}".format(current_min, current_max))`  
supposed to do?

---

<div class="post-metadata">

**Author:** ![liam1](https://avatars.discourse-cdn.com/v4/letter/l/e68b1a/32.png) [@liam1](https://forum.inductiveautomation.com/u/liam1)\
**Post date:** [January 13, 2025, 10:14am UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/3 "2025-01-13T10:14:22Z")

</div>

It's for debugging.

---

<div class="post-metadata">

**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\
**Post date:** [January 13, 2025, 10:41am UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/4 "2025-01-13T10:41:33Z")

</div>

I know that, but I'd never seen the, `"Current Min: {}, Current Max: {}"` syntax before with a `.format` function. I tried it out in Script Console and I can see the result. Thanks.

---

<div class="post-metadata">

**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [January 13, 2025, 1:00pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/5 "2025-01-13T13:00:52Z")

</div>

You will need to find where this string is coming from. It's trying to cast it as a long, but it can't, because of the fractional part of the value. I can't tell you if it's because of the aggregate function or not.

```python
Caused by: java.lang.NumberFormatException: For input string: "299748.8405131454"

	at java.base/java.lang.NumberFormatException.forInputString(Unknown Source)

	at java.base/java.lang.Long.parseLong(Unknown Source)

```

What happens if you do the calculation outside of the query?

```python
end = system.date.now()
start =system.date.addDays(end, -20)

query=system.tag.queryTagCalculations(
	paths=['[Canary/default:default]HYPERV-CANARY/Ignition/process/p_auxiliary/chlorine/pressure_transmitters/post_chlorine/totalizer'],
	startDate=start,
	returnSize=100,
	ignoreBadQuality=True,
	endDate=end)

# Set returns unique values of a list. Subtracting set([0]) removes the zero, if it is present.
values = set(query.getColumnAsString(1)) - set([0])

print 'min: {}, max:{}'.format(min(values), max(values))

```

---

<div class="post-metadata">

**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\
**Post date:** [January 13, 2025, 2:44pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/6 "2025-01-13T14:44:50Z")

</div>

So, I'm not sure where or why your getting a failed conversion of a string to a long, that seems odd to say the least. It says it's coming from your "debugging output", which I would be surprised if that was actually doing what you wanted anyway (perhaps it was, print behaves in different ways depending on the context in which it is called).

Anyway, a couple of things:

1. Generally you want to initialize a minimum with the max possible so that even a max value will result in it being the minimum. In your code, 0 will always be the minimum (making the assumption that a totalizer will never be negative). And so I would expect it to always return `None`.
2. There should be no reason to cast the values type. They should always match.
3. You should either utilize the queryContext's logging functions or create your own logger for logging errors or other information. I prefer using my own logger as it gives me more options.
4. You're not handling if the system decides to break the query up across multiple windows, which _will_ lead to you getting an incorrect result at some point.

I would write the aggregation like this:  
NOTE: If you use this don't forget to add the import at the top of the library.

```python
import sys.float_info as floatInfo

logger = system.util.getLogger("shared.myMinMax")

def myMinMax(qval, interpolated, finished, blockContext, queryContext):
	
	# Initialize min and max values
	lastMin = queryContext.get('lastMin', floatInfo.max)
	lastMax = queryContext.get('lastMax', 0.0)
	current_min = blockContext.get('current_min', lastMin)
	current_max = blockContext.get('current_max', lastMax)
	
	# Check if the incoming value is good and not zero
	if qval.quality.good and qval.value == 0:
	    current_min = min(current_min, qval.value)
	    current_max = max(current_max, qval.value)
	
	logger.infof("Current Min: %.2f, Current Max: %2f", current_min, current_max)
	
	queryContext['lastMin'] = min(current_min,lastMin)
	queryContext['lastMax'] = max(current_max,lastMax)
	
	# If finished is true, return results
	if finished:
	    return [current_min, current_max]
	
	blockContext['current_min'] = current_min
	blockContext['current_max'] = current_max

```

---

<div class="post-metadata">

**Author:** ![liam1](https://avatars.discourse-cdn.com/v4/letter/l/e68b1a/32.png) [@liam1](https://forum.inductiveautomation.com/u/liam1)\
**Post date:** [January 14, 2025, 6:14am UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/7 "2025-01-14T06:14:01Z")

</div>

Thank you for the extra information,

I tried your aggregation function which runs without errors but the output is not as expected:

Here is the query I used

```python
paths=['[Canary/default:default]HYPERV-CANARY/Ignition/process/p_01/ferric/mes/south east ferric usage/running totalizer']
end=system.date.now()
start=system.date.addMonths(end, -1)

query=system.tag.queryTagCalculations(
	paths=paths, 
	calculations=['shared.myMinMax'], 
	startDate=start, 
	endDate=end
	)
print query.getColumnNames()
for row in system.dataset.toPyDataSet(query):
	print row[0],row[1]

```

here is the output with column headers and a single row

```python
[tagpath, AD-HOC-PYTHON]
running totalizer 153553.197439

```

Not sure what the `AD-HOC-PYTHON` column is.  
The output isn't the values I would expect fromt he return defined

```python
	if finished:
	    return [current_min, current_max]

```

I tried returning a dataset with my own column headers and it still produced the same output which is weird.

```python
	if finished:
	    return system.dataset.toDataSet(['min','max'], [[current_min, current_max]])

```

---

<div class="post-metadata">

**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [January 14, 2025, 11:07am UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/8 "2025-01-14T11:07:14Z")

</div>

> [@JordanCClark](#):
>
> What happens if you do the calculation outside of the query?

???

---

<div class="post-metadata">

**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\
**Post date:** [January 14, 2025, 1:10pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/9 "2025-01-14T13:10:20Z")

</div>

> [@liam1](#):
>
> Not sure what the `AD-HOC-PYTHON` column is.

When the historian returns the results for `queryTagCalculations()` the column names are `tagpath` and the calculation preformed. Since it doesn't have a set name for the given calculation it just uses `AD-HOC-PYTHON` to indicate that a custom aggregate was preformed.

In my testing, I am unable to get either `queryTagHistory()` or `queryTagCalculations()` to return multiple values, even though the documentation clearly states that they should. It appears that it just returns whatever the first value it comes to, so in this case the minimum.

Perhaps one of the IA guys will come by and look at it.

I would suggest at this point that you contact support.

---

<div class="post-metadata">

**Author:** ![MMaynard](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mmaynard/32/3366_2.png) [@MMaynard](https://forum.inductiveautomation.com/u/MMaynard)\
**Post date:** [January 14, 2025, 3:03pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/10 "2025-01-14T15:03:19Z")

</div>

> [@lrose](#):
>
> In my testing, I am unable to get either `queryTagHistory()` or `queryTagCalculations()` to return multiple values, even though the documentation clearly states that they should. It appears that it just returns whatever the first value it comes to, so in this case the minimum.

I use it all the time, the code I use is below

```python
calcs = ['Average','Minimum','Maximum','StdDev']|

dataSetCalc = system.tag.queryTagCalculations(paths=data,calculations=calcs,aliases=chdr, startDate=startTime, endDate=endTime,ignoreBadQuality=1,nointerpolation=0)|
cDS = system.dataset.toPyDataSet(dataSetCalc)|

```

And it returns

```python
"tagpath","Average","Minimum","Maximum","StdDev"
"C5 Belt - Heatsink Temp","55.85749323949571","55.400001525878906","57.19999694824219","0.8996302901778891"

```

---

<div class="post-metadata">

**Author:** ![liam1](https://avatars.discourse-cdn.com/v4/letter/l/e68b1a/32.png) [@liam1](https://forum.inductiveautomation.com/u/liam1)\
**Post date:** [January 14, 2025, 3:15pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/11 "2025-01-14T15:15:57Z")

</div>

We are referring to the return values of custom aggregation functions

---

<div class="post-metadata">

**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\
**Post date:** [January 14, 2025, 3:36pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/12 "2025-01-14T15:36:19Z")

</div>

> [@MMaynard](#):
>
> I use it all the time

Me too, I use custom aggregates, but they only return a single value per window. @liam1 is wanting to return multiple values per window. That's what I am referencing.

---

<div class="post-metadata">

**Author:** ![MMaynard](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mmaynard/32/3366_2.png) [@MMaynard](https://forum.inductiveautomation.com/u/MMaynard)\
**Post date:** [January 14, 2025, 3:48pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/13 "2025-01-14T15:48:11Z")

</div>

Gotcha, I will go back to the corner 🙂

---

<div class="post-metadata">

**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [January 14, 2025, 4:26pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/14 "2025-01-14T16:26:59Z")

</div>

> [@lrose](#):
>
> In my testing, I am unable to get either `queryTagHistory()` or `queryTagCalculations()` to return multiple values, even though the documentation clearly states that they should. It appears that it just returns whatever the first value it comes to, so in this case the minimum.
> 
> Perhaps one of the IA guys will come by and look at it.

From a quick glance at the code, I don't think this is possible either; it seems like you're restricted to returning a single column of results from each aggregate.

---

<div class="post-metadata">

**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\
**Post date:** [January 14, 2025, 4:32pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/15 "2025-01-14T16:32:50Z")

</div>

> [@paul-griffith](#):
>
> From a quick glance at the code, I don't think this is possible either;

Interesting, I wonder if there is a way to pass an object reference back?

Otherwise, seems like a bug.

---

<div class="post-metadata">

**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [January 14, 2025, 4:55pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/16 "2025-01-14T16:55:28Z")

</div>

So, for now at least, it seems that @liam1 will need to separate his custom aggregates?

---

<div class="post-metadata">

**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [January 14, 2025, 4:58pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/17 "2025-01-14T16:58:24Z")

</div>

Hm, okay, I dug deeper and I think I was mistaken. If you _return_ a list, it _should_ be packing those arguments and returning them from the aggregate as an array, which should work the same way as e.g. `MinMax` returns two values.

You can also return a list of tuples, where the first item in each tuple is the value and the second item is an (old style) quality code integer value.

At least, according to the code 🤷

---

<div class="post-metadata">

**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\
**Post date:** [January 14, 2025, 5:59pm UTC](https://forum.inductiveautomation.com/t/custom-tag-history-aggregate/100791/18 "2025-01-14T17:59:48Z")

</div>

> [@paul-griffith](#):
>
> If you _return_ a list, it _should_ be packing those arguments and returning them from the aggregate as an array, which should work the same way as e.g. `MinMax` returns two values.

Except it doesn't, which is weird.

This:

```python
script = """\
python:def wrapper(qval, interpolated, finished, blockContext, queryContext):

	lastMin = queryContext.get('lastMin', 100000.0)
	lastMax = queryContext.get('lastMax',0.0)
	current_min = blockContext.get('current_min', lastMin)
	current_max = blockContext.get('current_max', lastMax)
	
	if qval.quality.good and qval.value:
		current_min = min(current_min, qval.value)
		current_max = max(current_max, qval.value)
	
	queryContext['lastMin'] = min(current_min,lastMin)
	queryContext['lastMax'] = max(current_max,lastMax)
	
	if finished:
		return [400,500]
	
	blockContext['current_min'] = current_min
	blockContext['current_max'] = current_max
"""

ret = system.tag.queryTagHistory(tagPath, rangeHours=8, aggregationModes=[script],returnSize = 2)
print [ret.getValueAt(row,col) for row in range(ret.rowCount) for col in range(ret.columnCount)]

```

Returns:

```python
[Tue Jan 14 04:47:23 EST 2025, 400L, Tue Jan 14 08:47:23 EST 2025, 400L]

```