Truncate a floating point number without rounding up

Question

I have a floating point number that I want to truncate to 3 places but I don\'t want to round up.

For example, convert 1.0155555555555555 to 1.015

Answer 1

Since ruby 2.4 Float#truncate method takes as an optional argument a number of decimal digits:

1.0155555555555555.truncate(3)
# => 1.015