Concatenating string with number in ruby

Question

I am total begineer in ruby so its very novice question.

I am trying to concatenate a string with a float value like follows and then printing it.

puts " Total Revenue of East Cost: " + total_revenue_of_east_cost

total_revenue_of_east_cost is a variable holding float value, how i can make it print?

Answer 1

This isn't exactly concatenation but it will do the job you want to do:

puts " Total Revenue of East Cost: #{total_revenue_of_east_cost}"

Technically, this is interpolation. The difference is that concatenation adds to the end of a string, where as interpolation evaluates a bit of code and inserts it into the string. In this case, the insertion comes at the end of your string.

Ruby will evaluate anything between braces in a string where the opening brace is preceded by an octothorpe.

Answer 2

Stephen Doyle's answer, using a technique known as "String interpolation" is correct and probably the easiest solution, however there is another way. By calling an objects to_s method that object can be converted to a string for printing. So the following will also work.

puts " Total Revenue of East Cost: " + total_revenue_of_east_cost.to_s

Answer 3

For your example, you might want something more specific than the to_s method. After all, to_s on a float will often include more or less precision than you wish to display.

In that case,

puts " Total Revenue of East Coast: #{sprintf('%.02f', total_revenue_of_east_coast)}"

might be better. #{} can handle any bit of ruby code, so you can use sprintf or any other formatting method you'd like.

Answer 4

I like (see Class String % for details):

puts " Total Revenue of East Cost: " + "%.2f" % total_revenue_of_east_coast