Programming can be confusing. Ruby language - ruby-on-rails

Question

I am here because I have recently decided to change careers, and considering both my parents are programmers I have always wanted to try out learning to code.
I want to apply to a little academy in San Francisco named App Academy but in order to move forward, I have to pass an exam for them. Their website is:
http://www.appacademy.io/
I've been reading a lot lately trying to prepare for their exam so to speak but somehow I'm still struggling to get the logic out of this. I feel like there are so many different ways of programming something, there are literally no limits sometimes.
In short, here is my 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)
end
Where I'm struggling is that I'm never sure where to start. Every time I attack a new problem somehow I can't figure out the logic. In this problem, please don't provide answers as I want to try it myself. However I would really appreciate some help on learning a methodology to apply for every problem.
For instance, here the first thing I realize is that every hour has 60 minutes so at some point I will have to include that in my answer. Do I have to create a loop? I think so. Keep in mind I DON'T KNOW how to write yet...Perhaps something like:
def time_conversion(minutes)
i = 0
while i > 60
return hours of integer i % 60
return minutes of remainder * 60
else return minutes of remainder * 60
end
I'm sure I got it all wrong....please HELP! Is the logic in the right direction though?

Answer 1

You're going to have to work backwards here. Formatting a string is easily done with the sprintf method, but how do you know what to put in that? Here's the target:
sprintf("%d:%02d", hours, minutes)
Calculating hours and minutes given seconds just requires math:
hours = minutes / 60
minutes = minutes % 60
Then you can combine those two and get your result.

Answer 2

You might be overthinking this. How about the following approach?
def minutes_timestamp(minutes)
"%d:%.2d" % [minutes/60, minutes % 60]
end
EDIT
tadman's answer is correct as well. The above example is equivalent to:
def minutes_timestamp(minutes)
sprintf("%d:%.2d", minutes/60, minutes % 60)
end
The "%d:%.2d" syntax is a bit cryptic, but it simply ensures the resulting string conforms to the HH:MM format, while also ensuring a leading zero for single digit minutes. There's a great tutorial that can explain sprintf and string formatting better than I can here: https://blog.udemy.com/ruby-sprintf/.

Answer 3

Welcome to Stack Overflow. Learning programming is very difficult task as you have to change how you approach problems. Also you need before starting to learn logic to know the syntax of language you are learning. In your case return statement will exit the function and thus not allowing you to go to minutes part.
I can only recommend this book http://poignant.guide/ for a start in Ruby as it's very funny (at least to me). It will help you understand a language. After it you should try solving the logic/approach problem now that you know what you can use.
For finding solutions I can only recommend you to use pen and paper and find a solution there. After you are sure of human logic, try to pretend that you are a computer with access only to data (written on paper and identified by name) and operations that you know code can do and mark the changes in data after each operation.
I.e. you as human know that 1,3,5,7,9... are odd numbers, but given a number x how can you know is it odd in code? This is simple: is_odd = x % 2 == 1 so you can use that part of code whenever you had to check if something is odd. So my advice is to try to approach the problems more as a machine then as a human.

Answer 4

Temporarily ignore the fact that a computer is involved, and pretend you're giving instructions to someone without any common sense, who will follow your instructions to the letter.
What is it that you want the person to do for you? In this case, turn a single number (of minutes) into two numbers (a number of hours, and then a number of minutes left over), and then put them side-by-side with a colon between them.
Because it isn't immediately obvious how to do this, you then break this down:
How can you turn a number of minutes into a number of hours (ignoring the remainder, the formatting etc.)?
Once you have some of the minutes represented as a number of hours, how can you work out the number of minutes left?
Once you have the two numbers, how can you package them up in the desired output representation?
If these steps are too complex to just write the answer to, break each of them down, and so on. The computer code is merely a final imprint of the design.

Answer 5

minutes = 246
"%02d:%02d" % minutes.divmod(60) #=> "04:06"
Fixnum#divmod don't get no respect.