Easiest Way to Print Non-Strings in Ruby

Question

I'm constantly doing this

puts “The temperature is “ + String(temperature) + “.”

in my debugging code, and another option is to use interpolation

puts “The temperature is #{temperature}.”

is there any less cumbersome way to do this?

Edit: This is just for debugging, if that matters.

Answer 1

None that are all that worthwhile for small cases like that.

Though, you should prefer interpolation as it's less expensive than concatenation.

Answer 2

The best way to insert dynamic variables into strings is

#interpolation
"foo #{my_var} bar"

It will call the to_s method on whatever object the expression returns and insert that string. It really the same as

#concatenation
"foo " + my_var.to_s + " bar"

But, as wfarr metioned, its faster to do interpolation. Easier to read too.

Answer 3

There's always the possibility to use printf style formatting:

"The temperature is %s" % temperature

This would allow for finer formatting of numbers, etc. as well. But honestly, how much less "cumbersome" than using #{} interpolation can you expect to get?

Answer 4

Another way is to do something stupid like this:

"The temperature is %s." % temperature.to_s

Personally I'd use interpolation

Answer 5

A slightly different approach is to use assertions in automated tests.

For example using Test::Unit :-

assert_equal 25, temperature

I find that using automated tests dramatically cuts down on the amount of debugging code I have to write.

Answer 6

Use Kernel#p

p temperature #=> 10.25

When I'm debugging, I often label such statements just by copying the line, and using inserting a colon, making the variable into a symbol.

p :attributes #=> :attributes
p attributes  #=> { :mood => "happy", 5 => [] }

Or

p [:location, location] #=> [ :location, "@ work" ]

Note that Kernel#p calls #inspect on its arguments, instead of #to_s, but this normally provides more useful debugging info anyway.