Utilityrate5.ElectricityRates.ur_ec_tou_mat a touple, does not support item assi

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Rob Frohne
Topic Author

24 Feb 2020 08:30 #7997 by Rob Frohne

Utilityrate5.ElectricityRates.ur_ec_tou_mat a touple, does not support item assi was created by Rob Frohne

Hi Paul,
It is time to go home here, but I thought I'd send you a query, since you are six or more hours ahead of me, and if I wait until tomorrow, it will delay an answer another day. :-)
I'm trying to change the utility rate, and finding it immutable. Maybe I need to use the assign method. Here is what I'm doing:

ur.ElectricityRates.ur_ec_tou_mat[0][4] = rate_sheet.cell_value(i, 1)
I get the following error:

   ur.ElectricityRates.ur_ec_tou_mat[0][4] = rate_sheet.cell_value(i, 1)
TypeError: 'tuple' object does not support item assignment

Any ideas?
And thanks!
Rob

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Paul Gilman

24 Feb 2020 22:01 #7998 by Paul Gilman

Replied by Paul Gilman on topic Utilityrate5.ElectricityRates.ur_ec_tou_mat a touple, does not support item assi

Hi Rob,

To assign values as they appear in this screenshot of the energy charge input table in the SAM user interface,

the 'ur_ec_tou_mat' array would be defined as (with line breaks and spacing to make it more legible):

ur_ec_tou_mat = 
[
[ 1, 1, 1+38, 0, 0.12, 0 ], 
[ 2, 1, 1+38, 0, 0.05, 0 ], 
[ 3, 1, 1+38, 0, 0.25, 0 ], 
[ 4, 1, 1+38, 0, 0.26, 0 ]
]

To assign the buy rate for Period 1, Tier 1 to $0.10/kWh, you would set:

ur_ec_tou_mat[0][4] = 0.1

So, that part of your assignment looks correct.

From the PySAM 2.0 documentation for the Utilityrate5 module, it looks like 'ur_ec_tou_mat' is a sequence: nrel-pysam.readthedocs.io/en/2.0.2/modules/Utilityrate5.html#module-PySAM.Utilityrate5.

The error message suggests that `ur.ElectricityRates.ur_ec_tou_mat` is a tuple. Tuples, unlike lists, are immutable in Python, so they can't be changed.

Is that enough information to solve the problem?

Thanks,
Paul.

...mat_sam_ui.png

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Rob Frohne
Topic Author

25 Feb 2020 02:17 #8003 by Rob Frohne

Replied by Rob Frohne on topic Utilityrate5.ElectricityRates.ur_ec_tou_mat a touple, does not support item assi

Thanks Paul,
You and I agree on everything here. You have nicely summarized things. Python does indeed think the type is tuple, and certainly tuples are not mutable.

type(ur.ElectricityRates.ur_ec_tou_mat)
Out[114]: tuple

This is unfortunate, because I need to modify the electric rates to make my rates change over time. I think I have all the code do do that put together now, but I was assuming that the rates were mutable. I'm not really a python programmer (yet), and I'm still stuck. There must be a way around this. Any other ideas?
Thanks,
Rob

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Rob Frohne
Topic Author

25 Feb 2020 03:45 #8004 by Rob Frohne

Replied by Rob Frohne on topic Utilityrate5.ElectricityRates.ur_ec_tou_mat a touple, does not support item assi

Hi Paul,
I found my answer. You convert the tuple to a list, and then make a new tuple with the values of the list. It seems to work.

temp_list = [list(x) for x in ur.ElectricityRates.ur_ec_tou_mat]
    temp_list[0][4] = rate_sheet.cell_value(i, 1)
    temp_list[1][4] = rate_sheet.cell_value(i, 2)
    ur.ElectricityRates.ur_ec_tou_mat = tuple(temp_list)

Thanks,
Rob

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Utilityrate5.ElectricityRates.ur_ec_tou_mat a touple, does not support item assi

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