Checking if a variable is not nil and not zero in ruby

You can take advantage of the `NilClass` provided `#to_i` method, which will return zero for `nil` values:

unless discount.to_i.zero?
# Code here
end

If `discount` can be fractional numbers, you can use `#to_f` instead, to prevent the number from being rounded to zero.

When dealing with a **database record**, I like to initialize all empty values with 0, using the migration helper:

add_column :products, :price, :integer, default: 0

From Ruby 2.3.0 onward, you can combine the safe navigation operator (`&.`) with [`Numeric#nonzero?`](

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). `&.` returns `nil` if the instance was `nil` and `nonzero?` - if the number was `0`:

if discount&.nonzero?
# ...
end

Or postfix:

do_something if discount&.nonzero?

def is_nil_and_zero(data)
data.blank? || data == 0
end

If we pass "" it will return false whereas blank? returns true.
Same is the case when data = false
blank? returns true for nil, false, empty, or a whitespace string.
So it's better to use blank? method to avoid empty string as well.

if discount.nil? || discount == 0
[do something]
end

Alternative solution is to use Refinements, like so:

module Nothingness
refine Numeric do
alias_method :nothing?, :zero?
end

refine NilClass do
alias_method :nothing?, :nil?
end
end

using Nothingness

if discount.nothing?
# do something
end

ok, after 5 years have passed....

if discount.try :nonzero?
...
end

It's important to note that `try` is defined in the ActiveSupport gem, so it is not available in plain ruby.

I prefer using a more cleaner approach :

val.to_i.zero?

`val.to_i` will return a `0` if **val** is a `nil`,

after that, all we need to do is check whether the final value is a **zero**.

Yes, we do have a clean way in ruby.

discount.to_f.zero?
This check handles good amount of cases i.e. discount may be nil, discount may be int 0, discount may be float 0.0, discount may be string "0.0", "0".