Rosetta Code

Narcissistic decimal number

Identify fixed sample numbers that equal the sum of their digits raised to the digit count.

Intro View source

Source rosettacode/popular/narcissistic_decimal_number.vibe

# title: Narcissistic decimal number
# source: https://rosettacode.org/wiki/Narcissistic_decimal_number
# category: Rosetta Code
# difficulty: Intro
# summary: Identify fixed sample numbers that equal the sum of their digits raised to the digit count.
# tags: popular, numbers, math, search
# vibe: 0.4

def narcissistic?(value)
  digits = value.to_s.chars
  digits.sum { |digit| digit.to_i ** digits.length } == value
end

def run
  [153, 370, 407, 408].map do |value|
    { value:, narcissistic: narcissistic?(value) }
  end
end

Output

Press run to execute run from this example.