Get type of all variables

Question

In R, I\'d like to retrieve a list of global variables at the end of my script and iterate over them. Here is my code

#declare a few sample variables
a<-1         


        

Answer 1

> mtcars %>% 
+     summarise_all(typeof) %>% 
+     gather
    key  value
1   mpg double
2   cyl double
3  disp double
4    hp double
5  drat double
6    wt double
7  qsec double
8    vs double
9    am double
10 gear double
11 carb double

I try class and typeof functions, but all fails.