Multiple aggregations of the same column using pandas GroupBy.agg()

As of 2022-06-20, the below is the accepted practice for aggregations: df.groupby(‘dummy’).agg( Mean=(‘returns’, np.mean), Sum=(‘returns’, np.sum)) Below the fold included for historical versions of pandas. You can simply pass the functions as a list: In [20]: df.groupby(“dummy”).agg({“returns”: [np.mean, np.sum]}) Out[20]: mean sum dummy 1 0.036901 0.369012 or as a dictionary: In [21]: df.groupby(‘dummy’).agg({‘returns’: {‘Mean’: np.mean, … Read more

C# Linq Group By on multiple columns [duplicate]

var consolidatedChildren = from c in children group c by new { c.School, c.Friend, c.FavoriteColor, } into gcs select new ConsolidatedChild() { School = gcs.Key.School, Friend = gcs.Key.Friend, FavoriteColor = gcs.Key.FavoriteColor, Children = gcs.ToList(), }; var consolidatedChildren = children .GroupBy(c => new { c.School, c.Friend, c.FavoriteColor, }) .Select(gcs => new ConsolidatedChild() { School = gcs.Key.School, … Read more

How to sum a variable by group

Using aggregate: aggregate(x$Frequency, by=list(Category=x$Category), FUN=sum) Category x 1 First 30 2 Second 5 3 Third 34 In the example above, multiple dimensions can be specified in the list. Multiple aggregated metrics of the same data type can be incorporated via cbind: aggregate(cbind(x$Frequency, x$Metric2, x$Metric3) … (embedding @thelatemail comment), aggregate has a formula interface too aggregate(Frequency … Read more

LINQ Aggregate algorithm explained

The easiest-to-understand definition of Aggregate is that it performs an operation on each element of the list taking into account the operations that have gone before. That is to say it performs the action on the first and second element and carries the result forward. Then it operates on the previous result and the third … Read more

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