I've noticed that small number floats, like 0.00000000345 end up getting converted to scientific notation, ie, 3.45e-9. This makes sense, but it looks like if I convert the float to a string (as I'd like to manipulate specific elements of the float according to its contents), the string itself adopts this notation.
Since it's now a string, it's easy enough to "translate" the contents back to a proper decimal number and manipulate it, but I was wondering if there is a built-in way that automatically allows for the saving of the actual decimal number as a string, rather than the scientific notation. Might not be, and I don't see anything in the documentation, but it can't hurt to ask.
With a round-trip to BigDecimal you can use its to_s method which allows the output format to be explicitly specified:
require 'bigdecimal'
require 'bigdecimal/util'
float = 0.00000000345
#=> 3.45e-09
float.to_d.to_s('F')
#=> "0.00000000345"
Note that Float#to_d attempts to determine the precision automatically which might fail for certain numbers:
float = 1.0.next_float
#=> 1.0000000000000002
float.to_d.to_s('F')
#=> "1.0"
Here, it might help to convert the float to a string in advance: (you also don't need to require bigdecimal/util using this variant)
BigDecimal(float.to_s).to_s('F')
#=> "1.0000000000000002"
Keep in mind that those outputs don't show the float's actual value. The exact decimal value for 0.00000000345 as a double-precision floating point number is:
0.000000003449999999999999873659487851216588760738801511251949705183506011962890625