r - I want to create a vector by using values of variables from a dataframe - 


data <- data.frame(cust_id = 1:5,                     a= (10,20,30,40,50),                     b=c(5,10,15,20,25),                     c=c(20,40,60,80,100),                    d=c(2,4,6,8,10))   vect <- c(a*2,b*3,c*4,d*5)

here need call values of a,b,c,d dataset respect cust_id 1:5 vector , multiply them 2,3,4,5 constants

vect<- c(40*2,20*3,80*4,8*5)

*note: vect vector, need output in vector form,

a,b,c,d values of variables data respect cust_id

we can use crossprod (if need multiply , sum)

crossprod(t(data[-1]), 2:5)

if need multiply corresponding columns vector

sweep(data[-1], 2, 2:5, "*")

or mapply

mapply(`*`, data[-1], 2:5)

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