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Accumulate column data

terapin

Community Trekker

Joined:

Jun 23, 2011

How do I use the lag operator to add up data on a row wise basis? That is, I want to accumulate data from column tair in a new column called chilling degree if the tair value is > 5.

tair chilling degree
5 5
7 5
5 10
2 REPLIES
afterword

Community Trekker

Joined:

Jun 23, 2011

I don't know the answer to this question, but it sounds like you're working with building energy data. Am I right? That's my field as well so I'd be happy to trade scripts and files with you.
If you want to simply accumulate values in a column, you don't necessarily need the lag operator. If you want to accumulate data (get a cumulative sum) for a column called "tair", do the following:

1. Create a new column. In this example, I call it "total".
2. Put the following formula in the new column:
(ignore this line)


The formula takes the value of tair in the current row, and adds it to the previous value of total, thus creating a cumulative sum.

If you only want to accumulate the values if they are greater than or equal to 5, then use the formula:

(ignore this line)

The formula looks at the current value of tair, and if it is less than 5, instead of adding tair, it adds 0.