Numeric calculations using dplyr piping commands

问题

Is it possible to use piping from the dplyr package to do numeric calculations? A simple example is:

    0.15 %>% 3.8416 * (.*(1-.))/(0.03^2)  #does not work
    seq(1,10,1) %>% log(.) %>% .^2        #works

Tying to understand more of how piping works and when it can and cannot be used. I really enjoy using the piping feature and want to find a way to use it for these types of numeric calculations.

Many thanks

回答1:

You have an operator precedence problem. It's trying to start by doing

0.15 %>% 3.8416

which doesn't make sense. You need to group all your calculations in a code block

0.15 %>% {3.8416 * (.*(1-.))/(0.03^2)}

回答2:

All of these are equivalent, you'll need magrittr for the first one, dplyr is enough for the next 2:

library(magrittr)
0.15 %>% multiply_by(subtract(1,.)) %>% multiply_by(3.8416) %>% divide_by(0.03^2)
0.15 %>% `*`(`-`(1,.)) %>% `*`(3.8416) %>% `/`(0.03^2)
0.15 %>% {3.8416 * (.*(1-.))/(0.03^2)}

来源：https://stackoverflow.com/questions/46836185/numeric-calculations-using-dplyr-piping-commands