From 0 to 1 is very difficult, hope everybody enlightenment, how do you start to learn block chain, recommended books or learning methods, thank you!!!!!!

CodePudding user response:

 
Lights_sum & lt; - flights_planes % & gt; % 
filter(! Is. Na (engines),! Is the na (seats)) % & gt; % 
Group_by (engines, seats) % & gt; % 
Summarize 

CodePudding user response:

 
The library (tidyverse)