How do you round a float to 2 decimal places in JRuby?

How do you round a float to 2 decimal places in JRuby(1.6.x)?

number = 1.1164
number.round(2)

# The above shows the following error
# wrong number of arguments (1 for 0)

(5.65235534).round(2)
#=> 5.65

sprintf('%.2f', number) is a cryptic, but very powerful way of formatting numbers. The result is always a string, but since you're rounding I assume you're doing it for presentation purposes anyway. sprintf can format any number almost any way you like, and lots more.

Full sprintf documentation: http://www.ruby-doc.org/core-2.0.0/Kernel.html#method-i-sprintf

Float#round can take a parameter in Ruby 1.9, not in Ruby 1.8. JRuby defaults to 1.8, but it is capable of running in 1.9 mode.

Edit

After getting feedback, It seems the original solution didn't work. That's why updated the answer as one of the suggestions.

def float_of_2_decimal(float_n) 
  float_n.to_d.round(2, :truncate).to_f
end

Other answers may work, if you want to have rounded numbers of 2 decimal places. But, If you want to have floating point numbers with first two decimal places without rounding, Those answers won't help.

So, to get a floating point number with first two decimal places, I used this technique. Doesn't work in some cases

def float_of_2_decimal(float_n)
  float_n.round(3).to_s[0..3].to_f
end

with 5.666666666666666666666666, it will return 5.66 instead of rounded 5.67. Hope it will help someone