why doesn't this ruby code work

Question

here's a practice question - Write a method that will take in a number of minutes, and returns a string that formats the number into hours:minutes.

def time_conversion(minutes)
    hours = minutes / 60
    mins = minutes % 60
    time = hours + ":" + mins
    return time
end

the following are tests to see if this works. if they return true then it means my code works correctly.

puts('time_conversion(15) == "0:15": ' + (time_conversion(15) == '0:15').to_s)
puts('time_conversion(150) == "2:30": ' + (time_conversion(150) == '2:30').to_s)
puts('time_conversion(360) == "6:00": ' + (time_conversion(360) == '6:00').to_s)

sometimes i get true for the first two tests but the third test line shows false even though the code will print out exactly the required.

other times I get the following error:

String can't be coerced into Fixnum (repl):4:in +' (repl):4:intime_conversion' (repl):1:in `initialize'

please assist.

You can't add a number to a string. Run irb and enter 5 + 'foo', and you'll get the same error. Try time = hours.to_s + ':' + mins.to_s in your time_conversion function. Or even just replace the entire function contents with return "#{minutes/60}:#{minutes % 60}" — lurker
– lurker, Commented Apr 19, 2016 at 2:32
wow. that did the trick. I haven't come across using the hashes, but that's interesting. I suppose that allows me to remove the mins and hours variable — hac13
– hac13, Commented Apr 19, 2016 at 2:50
Yes you could remove those variables. You should look up "ruby string formatting" if you want to have leading zeroes in your minutes, like 6:05. Your time_conversion won't create 6:00. It will create 6:0. — lurker
– lurker, Commented Apr 19, 2016 at 2:51
aahhh yeaa. I need to add the leading zero if the minutes were less than 10. (as a string) but this is great. I'm loving all this. thanks! — hac13
– hac13, Commented Apr 19, 2016 at 3:00

linY · Accepted Answer · 2016-04-19 03:09:31Z

1

The error mainly refers to this line time = hours + ":" + mins

hours & mins are Fixnum, whereas ":" is String As the error message indicates, "String can't be coerced into Fixnum".

You could either do time = hours.to_s + ":" + minutes.to_s or time = "#{hours}:#{minutes}".

answered Apr 19, 2016 at 3:09

linY

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3 Comments

hac13 Over a year ago

yup, lurker pointed me to the same. I like the final suggestion there. it's nice and concise thanks!

linY Over a year ago

thanks for the upvote,, actually my first ans on stackoverflow!

hac13 Over a year ago

that's cool. see you on the other side when I'm up and running myself

sawa · Accepted Answer · 2016-04-19 02:16:44Z

0

Because Fixnum#+ takes a Numeral argument, not a String.

answered Apr 19, 2016 at 2:16

sawa

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1 Comment

hac13 Over a year ago

my first question here and I got a super fast reply. thank you!

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