sumaafaizy sumaafaizy - 1 month ago 8
R Question

R Programming Syntax

This is for R programming. I have two vectors: numbers1 and numbers2 with integer elements in them. I want to calculate the element­wise products of n​umbers1​ and numbers2.​ For example, in numbers1, the first value is 3 and in numbers2 the first value is 2. What would be the syntax?

This reminds me of array elements in Java but I'm unable to conclude how to multiply them. I am new to R programming.

Answer

Agreed that this is a very basic R question, but just in case a brief "cheat sheet" is helpful to OP or some other user:

A = c(1,2,3,4,5)
B = c(2,2,2,2,2)

> A * B
   [1]  2  4  6  8 10
> A + B
   [1] 3 4 5 6 7
> A / B
   [1] 0.5 1.0 1.5 2.0 2.5
> A - B
   [1] -1  0  1  2  3
> A ^ B
   [1]  1  4  9 16 25

If you wanted to multiply, say, the first integer in A and B, you could do:

A[1] * B[1]

...or any combination therein.

For multiple integers in each vector, you'd do:

A[1:2] * B[1:2]

or

A[c(1, 3)] * B[c(1, 3)]
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