divide an array by the size

For example,i have an array :[2,4,6,7,9,12,1],i want to divide it by the size [2,2,3]

the output that i want is:

[[2,4],[6,7],[9,12,1]]

The way looks correct, you can do it more succinctly using 

map

 instead
of 

each

:

c = b.map{|m| a.shift(m)}

Or, using 

&method

 shorthand:

c = b.map(&a.method(:shift))
# => [[2, 4], [6, 7], [9, 12, 1]]