CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-3
yagmurdursun
yagmurdursun

Reputation: 943

get fraction part of a decimal number

I am trying to get a fraction part of a decimal number in rails. For example I have a number, that "1.23" and I want to get "23" It is may be too easy but, does anyone have any idea about how can I do?

Upvotes: 35

Views: 25003

Answers (9)

Sudhir Vishwakarma
Sudhir Vishwakarma

Reputation: 805

There are various ways we can achieve the output modulo is one of them

1.23.modulo(1) => 0.22999999999999998

you can round the result as per your convenience

but to achieve what you have asked in your question

I will follow a very simple approach 

value = 1.23.to_s.split('.') -> ["1", "23"]
value.last.to_i -> "23"

Upvotes: 1

Jonas Elfström
Jonas Elfström

Reputation: 31428

n = 1.23

n.modulo(1)
=> 0.22999999999999998

n - n.to_i
=> 0.22999999999999998

Recommended read http://floating-point-gui.de/

Upvotes: 10

Lucas Castro
Lucas Castro

Reputation: 31

..."1.23" and I want to get "23".

Just remove the integer part and multiply per 100.

((number - number.to_i) * 100).to_i

Upvotes: 2

slindsey3000
slindsey3000

Reputation: 4271

After trying everything... I feel the best answer is (num - num.to_i).abs because it also works for negative numbers.

e.g.

(1.23 - 1.23.to_i).abs = 0.23

(-1.23 - -1.23.to_i).abs = 0.23

Upvotes: -1

bloudermilk
bloudermilk

Reputation: 18109

Deciding on the proper solution requires understanding the type that you're working with. If your values are Float (the standard type for non-whole numbers in Ruby) then logically correct answers like mod(1) may produce unexpected results due to floating point errors. For any case where Float is the proper data type to be using in the first place, this is likely acceptable.

If floating point errors are not acceptable, don't use Float! Ruby comes with the great BigDecimal class which is much more accurate at the cost of performance and a slightly more verbose syntax.

decimal = BigDecimal.new("1.23")
decimal.frac #=> 0.23

Upvotes: 6

dsk
dsk

Reputation: 657

 a=1.23 #value of a will be 1.23
 a=a-a.to_i #value of a will be 0.23

Upvotes: 1

bioffe
bioffe

Reputation: 6383

if you know your desired precision, this might be a tad faster to to_s solution. 

1.1234.modulo(1).round(4) #0.1234

Upvotes: 6

EfratBlaier
EfratBlaier

Reputation: 559

I am not sure if it is the easiest way to do it - but you can simply split the number using "." character - like this:

number = 1.23
parts = number.to_s.split(".")
result = parts.count > 1 ? parts[1].to_s : 0

Upvotes: 11

Eugene Dorian
Eugene Dorian

Reputation: 917

Try to use modulo method:

1.23.modulo(1) => 0.23

Read more here: http://www.ruby-doc.org/core-1.9.3/Numeric.html#method-i-modulo

Or you can convert float to integer and substract it from original float value.

1.23 - 1.23.to_i => 0.23

Upvotes: 65

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