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Ruby has a built in function round() which allows us to both change floats to integers, and round floats to decimal places. round() with no argument will round to 0 decimals, which will return an integer type number. Using round(1) will round to one decimal, and round(2) will round to two decimals.
Ruby | Numeric round() function The round() is an inbuilt method in Ruby returns a number rounded to a number nearest to the given number with a precision of the given number of digits after the decimal point. In case the number of digits is not given, the default value is taken to be zero.
The round() method can be used to round a number to a specified number of decimal places in Ruby. We can use it without a parameter ( round() ) or with a parameter ( round(n) ). n here means the number of decimal places to round it to.
Ruby Language Numbers Rounding Numbers The round method will round a number up if the first digit after its decimal place is 5 or higher and round down if that digit is 4 or lower.
Pass an argument to round containing the number of decimal places to round to
>> 2.3465.round
=> 2
>> 2.3465.round(2)
=> 2.35
>> 2.3465.round(3)
=> 2.347
When displaying, you can use (for example)
>> '%.2f' % 2.3465
=> "2.35"
If you want to store it rounded, you can use
>> (2.3465*100).round / 100.0
=> 2.35
you can use this for rounding to a precison..
//to_f is for float
salary= 2921.9121
puts salary.to_f.round(2) // to 2 decimal place
puts salary.to_f.round() // to 3 decimal place
You can add a method in Float Class, I learnt this from stackoverflow:
class Float
def precision(p)
# Make sure the precision level is actually an integer and > 0
raise ArgumentError, "#{p} is an invalid precision level. Valid ranges are integers > 0." unless p.class == Fixnum or p < 0
# Special case for 0 precision so it returns a Fixnum and thus doesn't have a trailing .0
return self.round if p == 0
# Standard case
return (self * 10**p).round.to_f / 10**p
end
end
You can also provide a negative number as an argument to the round method to round to the nearest multiple of 10, 100 and so on.
# Round to the nearest multiple of 10.
12.3453.round(-1) # Output: 10
# Round to the nearest multiple of 100.
124.3453.round(-2) # Output: 100
def rounding(float,precision)
return ((float * 10**precision).round.to_f) / (10**precision)
end
what about (2.3465*100).round()/100.0?
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