CODEWITHSUNDEEP
ruby
Ryan-Neal Mes
Ryan-Neal Mes

Reputation: 6263

How to get 10s, 100s, 1000s from an integer?

Is there a method in ruby that allows breaking integers up into 1s, 10s, 100s, 1000s, ...?

I know that you can convert an integer to a string and parse the string to get the values mentioned above, but I would imagine there is a really simple way to do this with ruby like most other things. So far I have this:

1234.to_s.chars.reverse.each_with_index
.map{|character, index| character.to_i * 10**index }
# => [4, 30, 200, 1000]

But is there something specific to do this in ruby?

Upvotes: 1

Views: 274

Answers (3)

vgoff
vgoff

Reputation: 11313

def value_of_powers(number, base: 10)
  number.to_s.reverse.each_char.with_index.map do |character, index|
    base**index * character.to_i
  end.reverse
end

value_of_powers(10212, base: 3) # => [81, 0, 18, 3, 2]
value_of_powers(1234)           # => [1000, 200, 30, 4]

I reversed the order so that the values are read in the same order as we read numbers.

As shown, it also works for other base numbers. Given no base, it will default to base 10.

Upvotes: 1

Cary Swoveland
Cary Swoveland

Reputation: 110675

You could do that as follows:

n = 1020304

Math.log10(n).ceil.times.with_object([]) do |i,a|
  n, d = n.divmod(10)
  a << d * 10**i
end
  #=> [4, 0, 300, 0, 20000, 0, 1000000]

Hmmm. That looks a bit odd. Maybe it would be better to return a hash:

Math.log10(n).ceil.times.with_object({}) do |i,h|
  n, d = n.divmod(10)
  h[10**i] = d
end
  #=> {1=>4, 10=>0, 100=>3, 1000=>0, 10000=>2, 100000=>0, 1000000=>1}

Upvotes: 2

user12341234
user12341234

Reputation: 7203

This isn't particularly clever, but I suppose it's relatively clear about what it does.

def tens_places(n, place = 1)
  if n >= 1
    [(n % 10).floor * place] + tens_places(n/10, place * 10)
  else
    []
  end
end

Upvotes: 0

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