Difference between .nil?, .empty?, .bank?, .present? and .any?

Ruby Syntax Tips Henry Le

.nil?

It is a Ruby method.

It can be used on any objects and will return true if the object is “null”.

.nil? examples

nil.nil? = true ( “Only the object nil responds true to .nil?” – RailsAPI )

anthing_else.nil? = false

.empty?It is a Ruby method.

Can be used on strings, arrays and hashes and will return true if their lengths are zero.

Running .empty? on something that is nil will throw a NoMethodError.

.empty? examples[].empty? = true

{}.empty? = true

"".empty?= true

" ".empty? = false

nil.empty? => “NoMethodError: undefined method `empty?' for nil:NilClass"

.blank?It is a Rails method (in ActiveSupport).

Operate on any object as well as work like .empty? on strings, arrays and hashes.

It also evaluates true on strings which are non-empty but contain only whitespace.

.blank? examplesnil.blank? = true

" ".blank? = true

"\n\t\t".blank? = true

[" “].blank? = false

[nil].blank? = false

.present?

It is a Rails method (in ActiveSupport).

It is vice versa from .blank?

!obj.blank? == obj.present?

.present? examplesnil.present? = false

false.present? = false

true.present? = true

[].present? = false

[“"].present? = true

[nil].present?

.any?

Pass each elements of the collection to the given block the returns true if the block ever returns a value other than false or nil.

.any? examples[nil, false].any? = false

We can customise the condition to return true:

[nil, false].any? { |w| w == false } = true

%w{ant bear cat}.any? { |word| word.length >= 3 } = true

.present? vs .any?

[nil, false].present? = true

[nil, false].any? = false

Conclusion