I'm looking to get a column sum for a dataframe using Gota's cool dataframe in go.

I see from here that there's a way to apply functions to series which seems fine, that is doing:

mean := func(s series.Series) series.Series {
    floats := s.Float()
    sum := 0.0
    for _, f := range floats {
        sum += f
    }
    return series.Floats(sum / float64(len(floats)))
}
df.Cbind(mean)
df.Rbind(mean)

eg, just remove the division to get the sum function rather than the mean. That said, if I'm only looking to sum 1 column, am I stuck writing my own easy sum function, or is there something more idiomatic and built-in like R's

sum(df[,c("mycol")])

?

I'm currently working with:

    sum := func(s series.Series) series.Series {
    floats := s.Float()
    sum := 0.0
    for _, f := range floats {
        sum += f
    }
    return series.Floats(sum)
    }

df.Select([]string{"mycol"})).CBind(sum)

where df after I subset to only the column of interest becomes:

[31x1] DataFrame

    mycol
 0: 8.300000            
 1: 8.300000            
 2: 16.750000           
 3: 9.030000            
    ...                 
    <float>             

And I get something like:

cannot use sum (type func(series.Series) series.Series) as type dataframe.DataFrame in argument to df.Select([]string literal).CBind

UPDATE

Ah, partial solution in that the documentation uses Cbind/Rbind where I think Capply/Rapply was meant, as these are documented here. That said, the idiom question stands in that it would be great if there are built-ins I'm missing.