Why does && in Ruby sometimes shortcut evaluates and sometimes doesnt? -

i want test if element in hash exists , if >= 0, put true or false array:

boolean_array << input['amount'] && input['amount'] >= 0

this raises no >= on nilclass error. however, if this:

input['amount'] && input['amount'] >= 0   #=> false

no problem. basically:

false && (puts 'what heck?') #=> false arr = [] arr << false && (puts 'what heck?') #=> stdout: 'what heck?' arr #=> [false]

what gives?

currently it's being grouped as:

(boolean_array << input['amount']) && input['amount'] >= 0

try:

boolean_array << (input['amount'] && input['amount'] >= 0)

however, if ends being false, expression returns nil, want:

boolean_array << (!input['amount'].nil? && input['amount'] >= 0)

Business