# Can I modify an entire column from a dataset with system.dataset.setValue()? **URL:** \ **Category:** Ignition\ **Tags:** python, vision, scripting\ **Created:** [March 8, 2024, 3:39pm UTC](https://forum.inductiveautomation.com/t/can-i-modify-an-entire-column-from-a-dataset-with-system-dataset-setvalue/87043 "2024-03-08T15:39:29Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![nbautomation](https://avatars.discourse-cdn.com/v4/letter/n/3be4f8/32.png) [@nbautomation](https://forum.inductiveautomation.com/u/nbautomation)\ **Post date:** [March 8, 2024, 3:39pm UTC](https://forum.inductiveautomation.com/t/can-i-modify-an-entire-column-from-a-dataset-with-system-dataset-setvalue/87043/1 "2024-03-08T15:39:29Z")
Hi, I need to modify an entire colum from a dataset. I'm trying to do it with a cycle 'for' and 'system.dataset.setValue' but the cycle for only modified the last cell of the colum This is my example code: ```auto table = event.source.parent.getComponent("Table") dataIn = system.dataset.toPyDataSet(table.data) ``` `values=[10,20,30]` ```auto for n in range(0,2): table.data=system.dataset.setValue(dataIn, n, "columnIntegers", values[n]) print( n ,"times") ``` When I run the script, only edited the last cell, which has the int 30 And I checked the Output console and show _0 times_ _1 times_ _2 times_ I think system.dataset.setValue is not the best way but I'm noob on this Y tried doing the cycle 'manual' and I obtained the same result how can I code it? ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [March 8, 2024, 3:51pm UTC](https://forum.inductiveautomation.com/t/can-i-modify-an-entire-column-from-a-dataset-with-system-dataset-setvalue/87043/2 "2024-03-08T15:51:23Z")
`system.dataset.setValue()` doesn't modify the source dataset. It makes a new dataset with the change request. You would need to re-assign to `dataIn` within the loop, and then assign `dataIn` to the target property after the loop is done. That aside, this is terribly inefficient. I recommend using `system.dataset.filterColumns()` to drop the old column completely, then `system.dataset.addColumn()` to add it back with the new data. Construct just the new data in the loop (or perhaps in a list comprehension). ---
**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:** [March 8, 2024, 4:23pm UTC](https://forum.inductiveautomation.com/t/can-i-modify-an-entire-column-from-a-dataset-with-system-dataset-setvalue/87043/3 "2024-03-08T16:23:52Z")
```python def mapColumn(function, dataset, column): if isinstance(column, basestring): column = dataset.getColumnIndex(column) columnData = map(function, dataset.getColumnAsList(column)) columnsToKeep = range(dataset.columnCount) columnsToKeep.pop(column) dsWithoutColumn = system.dataset.filterColumns(dataset, columnsToKeep) return system.dataset.addColumn( dsWithoutColumn, column, columnData, dataset.getColumnName(column), dataset.getColumnType(column) ) ``` It's relatively easy to create a 'mapColumn' function composed of our base primitives. This will be pretty efficient. Usage is pretty simple - just declare a function that performs the calculation you want, for each value in the column, then supply it (no parenthesis!) to the mapColumn function: ```python # usage: def updateColumn(value): return value * 2 updatedDs = mapColumn(updateColumn, ds, "b") ``` On my test dataset, this does what you'd expect: ```auto a | b | c 1 | 2 | 3 4 | 5 | 6 a | b | c 1 | 4 | 3 4 | 10 | 6 ``` ---
**Author:** ![nbautomation](https://avatars.discourse-cdn.com/v4/letter/n/3be4f8/32.png) [@nbautomation](https://forum.inductiveautomation.com/u/nbautomation)\ **Post date:** [March 8, 2024, 5:01pm UTC](https://forum.inductiveautomation.com/t/can-i-modify-an-entire-column-from-a-dataset-with-system-dataset-setvalue/87043/4 "2024-03-08T17:01:39Z")
Thanks! It works! ---
**Author:** ![nbautomation](https://avatars.discourse-cdn.com/v4/letter/n/3be4f8/32.png) [@nbautomation](https://forum.inductiveautomation.com/u/nbautomation)\ **Post date:** [March 11, 2024, 1:35pm UTC](https://forum.inductiveautomation.com/t/can-i-modify-an-entire-column-from-a-dataset-with-system-dataset-setvalue/87043/5 "2024-03-11T13:35:37Z")
Now I'm trying to do something more than Just do a calcule for a specific column. I have a List with float tags provided from Tags OPC (No problem obtaining this values) and I need to put them in specific column on the same orden Column/position0= List[0] Column/position1=List[1] ... Column/position n=List[n] Where List contain the values of tags and 'n' is a knowed parameter I was trying with a function similar But I only could put the same value of the List in all rows of the column I'm sorry if the solution is so obvious and dumb for you. I'm new with this Framework and Python. Each Time I try to do somethings more complex for me I try put the list on the first parameter but the error said "list is not calleable" Then I tried to do a for ```auto for n in range(0,index_knowed): updatedDs = mapColumn(values[n], table.data, "GRUESO") table.data=updatedDs ``` _TypeError: 'float' object is not callable_ Values is a list with float values. I tried to make `integer_Values[n]= int(values[n])` inside the for but The error was _TypeError: 'int' object is not callable_ Can anyone guide me? ---
**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:** [March 11, 2024, 2:40pm UTC](https://forum.inductiveautomation.com/t/can-i-modify-an-entire-column-from-a-dataset-with-system-dataset-setvalue/87043/6 "2024-03-11T14:40:58Z")
Is this already in the dataset, or are you adding a column to the dataset? ---
**Author:** ![nbautomation](https://avatars.discourse-cdn.com/v4/letter/n/3be4f8/32.png) [@nbautomation](https://forum.inductiveautomation.com/u/nbautomation)\ **Post date:** [March 11, 2024, 3:08pm UTC](https://forum.inductiveautomation.com/t/can-i-modify-an-entire-column-from-a-dataset-with-system-dataset-setvalue/87043/7 "2024-03-11T15:08:32Z")
I saw my error, the differences between the example code posted for @paul-griffith and what I needed it, it was in the map function, because I already had the List for put in the third Parameter of > system.dataset.addColumn(dataset, [colIndex], col, colName, colType) so that I did put them and everything works I couldn't see until now. Thanks 🤝🏼