python expression

GregorMitzlaff

Hello everybody,

in the picture you can see an attribute table of an heat meter. The number of the heat meter is 11250423. The heat status is given monthly. Now I want to make an expression to get the consumption of every month.

in theory I have to do sth like this:

y_(i+1)-y_(i) = consumption

Month 1 (january): y_(1+1)-y_(1) = consumption of January

Month 2 (feb): y_(2+1)-y_(2) = consumption of February

...

Month 12 (dec): y_(12+1)-y_(12) = consumption of December

does anybody know, how to write an expression in arcgis? I want to make a new field to calculate.

Thanks for helping.

Greets from Germany!

Arne_Gelfert

Gregor,

I'm sure what you're trying to accomplish can be done in field calculator. In my experience, the more massaging I have to do with data, the more I want to do it near the source. Usually that's fastest and I find it more transparent. Don't know where you're getting your data. But this would be easy to do in SQL:

<SPAN class="keyword token">SELECT</SPAN> month<SPAN class="punctuation token">(</SPAN>Datum<SPAN class="punctuation token">)</SPAN> <SPAN class="keyword token">AS</SPAN> <SPAN class="punctuation token">[</SPAN>MONTH<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> year<SPAN class="punctuation token">(</SPAN>Datum<SPAN class="punctuation token">)</SPAN> <SPAN class="keyword token">AS</SPAN> <SPAN class="punctuation token">[</SPAN>YEAR<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="token function">SUM</SPAN><SPAN class="punctuation token">(</SPAN>Wärmemenge<SPAN class="punctuation token">)</SPAN> <SPAN class="keyword token">AS</SPAN> TOTAL
<SPAN class="keyword token">FROM</SPAN> <SPAN class="operator token"><</SPAN>YOUR <SPAN class="keyword token">DATA</SPAN> SOURCE<SPAN class="operator token">></SPAN>
<SPAN class="keyword token">GROUP</SPAN> <SPAN class="keyword token">BY</SPAN> month<SPAN class="punctuation token">(</SPAN>Datum<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">,</SPAN> year<SPAN class="punctuation token">(</SPAN>Datum<SPAN class="punctuation token">)</SPAN>
<SPAN class="comment token">-- ORDER BY [MONTH], [YEAR]</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

So admittedly, this may not work in in your situation but if it does and you can create a query layer or database view, I bet it would perform better.

Schöne Grüße