Rilcon42 Rilcon42 - 1 year ago 70
R Question

get sum of the product of two columns

Can someone explain how my order of operations for the R fuctions below is wrong? I expected to multiply across each row then sum the result, but the answer I got was very different.

qqq%>%sum(.[,1]*.[,2]) #returns: 53

# answer I expected: 1*4+2*5+3*6 = 32

Answer Source

We can try

qqq %>%
     Reduce(`*`, .) %>%
#[1] 32
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