(Ruby) Padding single digits when it comes to time - ruby

I have 2 methods in a Timer class I'm creating. One method is where hours, minutes, and seconds are calculated from any given amount of seconds and the other method will pad any single digits with a "0". Every things I've look up so far isn't work for me. Below is my code:
class Timer
attr_accessor :seconds=(time), :time_string
def initialize(seconds = 00)
#seconds = seconds
end
def time_string
hours = padded((#seconds/3600)
minutes = padded(#seconds/60 - hours * 60)
seconds = padded(#seconds%60)
puts '#{hours):#{minutes}:#{seconds}'
end
def padded(x)
if x.length == 1
"0"+x
end
end
end
so if I put in 7683, the output I want to get is "02:08:03". but when I execute it, I get the following error message:
(eval):6: (eval):6:in `-': String can't be coerced into Fixnum (TypeError)
from (eval):6:in `time'
from (eval):19
I'm confused where this is erroring out.

To answer your question as to why your code is not working, you have got couple of conversion issues between FixNum and String throughout your code, you can fix it as follows:
def time_string(seconds)
hours = seconds/3600
minutes = seconds/60 - (hours * 60)
seconds = seconds%60
puts padded(hours)+':'+padded(minutes)+':'+padded(seconds)
end
You use the hours variable in the second statement, but because its already converted to string, it crashes, therefore its better to do all the calculations first, and only later use the padded method which returns the padded digits in string format. The padded method must also be modified to be consistent:
def padded(x)
if x.to_s.length == 1
return "0"+x.to_s
else
return x.to_s
end
end
Just keep in mind that the combination of the two methods will work only for numbers up to 86399, which will return 23:59:59. Any number passed to time_string bigger than that will pass the 24 hour mark and will return something like: 26:00:00

There is a brilliant method for padding, why not use it?
3.to_s.rjust(10,"*") #=> "*********3"
4.to_s.rjust(2,"0") #=> "04"
44.to_s.rjust(2,"0") #=> "44"
If you want a better solution than writing your own class, use at
Time.at(7683).strftime("%H:%M:%S") #=> "02:08:03"

There's no need to reinvent the wheel.
t = 7683 # seconds
Time.at(t).strftime("%H:%M:%S")
Time.at(seconds) converts your seconds into a time object, which then you can format with strftime. From the strftime documentation you can see you can get the parameters you want non padded, white padded or zero padded.

I tend to use something like this
"%02d" % 2 #=> 02
"%02d" % 13 #=> 13
It's part of the Kernel module: http://ruby-doc.org/core-2.1.3/Kernel.html#M001433

Related

Adding together string-based minutes and seconds values

I have a a Track model that has a duration attribute. The attribute is string based, and reads in minutes:seconds format. I was wondering what the best way would be to take these string-based values and add them together. For example, if there are duration values like this:
Duration 1: "1:00"
Duration 2: "1:30"
how could I get it to output "2:30"?
Most of the questions I found related to this issue start with an integer based value. What's the best way to get this done?
My suggestion is to store/manipulate them as seconds.
It's definitely easier to store them as the integer number of seconds, and apply a function to parse/format the value into the proper string representation.
Storing them as integer will make it very easy to sum and subtract them.
Here is one way this can be done:
class Track
attr_accessor :duration
def initialize(duration)
#duration = duration
end
end
arr = [Track.new("1:00"), Track.new("1:30")]
total_seconds = arr.reduce(0) do |a, i|
min, sec = i.duration.split(":").map(&:to_i)
a + min * 60 + sec
end
p total_duration = '%d:%02d' % total_seconds.divmod(60)
#=> "2:30"
Edit: I missed #Wand's earlier answer, which is the same as mine. I'll leave mine just for the way I've organized the calculations.
arr = %w| 1:30 3:07 12:53 |
#=> ["1:30", "3:07", "12:53"]
"%d:%2d" % arr.reduce(0) do |tot,str|
m,s = str.split(':')
tot + 60*m.to_i + s.to_i
end.divmod(60)
#=> "17:30"
I just had to implement something like this in a recent project. Here is a simple start. If you are sure you will always have this format 'H:S', you will not need to convert your duration to time objects:
entries = ["01:00", "1:30", "1:45"]
hours = 0
minutes = 0
entries.each do |e|
entry_hours, entry_minutes = e.split(':', 2)
hours += entry_hours.to_i
minutes += entry_minutes.to_i
end
hours += (minutes/60)
minutes = (minutes%60)
p "#{hours}:#{minutes}"
#=> "4:15"
I agree with #SimoneCarletti: store them as an integer number of seconds. However, you could wrap them in a duration value class that can output itself as a nicely formatted string.
class Duration
attr_accessor :seconds
def initialize(string)
minutes, seconds = string.split(':', 2)
#seconds = minutes.to_i * 60 + seconds.to_i
end
def to_s
sprintf("%d:%02d", #seconds / 60, #seconds % 60)
end
def self.sum(*durations)
Duration.new(durations.reduce(0) { |t,d| t + d.seconds })
end
end
EDIT: Added a sum method similar to that suggested by #CarySwoveland below. You can use this as follows:
durations = ["1:30", "2:15"].map { |str| Duration.new(str) }
total = Duration.sum *durations

How can I make the minutes variable two digits?

I'm trying to get the minutes to show two digits even when a single digit answer is assigned to the min_side variable. It's probably a simple answer but I cannot seem to get it to work.
def time_conversion(minutes)
hour = minutes/60
min_side = minutes%60
min_side = %02d
time = "#{hour}:#{min_side}"
return time
end
puts time_conversion(360)
You can use sprintf:
def time_conversion(minutes)
hour = minutes / 60
min_side = minutes % 60
sprintf("%d:%02d", hour, min_side)
end
you can use rjust to add zeros
minutes.to_s.rjust(2, '0')
You could do it like so:
def time_conversion(minutes)
"%d:%02d" % minutes.divmod(60)
end
puts time_conversion(360)
#=> "6:00"
def time_conversion(minutes)
hour = minutes/60
min_side = minutes%60
"#{hour}:#{min_side < 10 ? "0#{min_side}" : min_side}"
end
By the way, the latter part of the last line is not a comment. It's a nested string interpolation that a code formatting here cannot recognize
Low readability, in-place perl'ish way :)
time = "#{hour}:#{"0#{min_side}"[-2,2]}"
Adds zero and gets last two chars of the result.

Ruby inject method

I'm doing some ruby exercises. In one of the solutions of my exercise, I found this code.
def make_change(amount)
{ H:50, Q:25, D:10, N:5, P:1 }.inject({}) do |res, (k,v)|
change, amount = amount.divmod(v)
res[k] = change unless change==0
res
end
end
This method takes an amount as parameter and associates coins to equal it. For example:
make_change(75)
#=> {H:1, Q:1}
(50 + 25 = 75)
But I don't understand where the change variable come from. How is the variable filled?
But i doesnt understand where does the "change" variable come from, how the variable is filled ?
change is defined and initialized in the first line of the block:
change, amount = amount.divmod(v)

How do I parse a simple time string into a time period?

In my Ruby app, I have an Investment entity that has a term attribute.
I need this class to accept a String from user input in the form of 3 Years or 36 months. What I want is to then convert the input into number of months, set the term attribute to this period and figure out the maturity date.
So far I have tried using Active Support and Chronic but the APIs do not support this.
This getter works:
def term
if term =~ /year[s]?/i
term = term.to_i * 12
else term =~ /month[s]?/i
term = term.to_i
end
end
But is there a more elegant way to do this in Ruby?
Ruby doesn't have anything built-in that represents a "time-span" (some other languages do). However, there is a library for it (timespan), although it may be a bit overkill for your situation.
You mentioned that chronic doesn't support this. But why not just calculate the time difference yourself?
require 'chronic'
input = '2 years'
then = Chronic.parse(input + ' ago')
now = Time.now
# Now we just calculate the number of months
term = (now.year * 12 + now.month) - (then.year * 12 + then.month)
That way, you get the flexibility of chronic's parsing, and you still don't need much code.
Or just go ahead and use the timespan library.
require 'timespan'
term = Timespan.new('2 years').to_months
# Boom.
If we can assume that the input string will always contain one or more digits followed a unit ("years", "Year", "months", etc.), this is pretty straightforward. Just write a regular expression that captures the digits and the unit, convert the digits to a number and normalize the unit, and do the math.
def to_months(str)
if str =~ /(\d+)\s*(month|year)s?/i
num = $1.to_i # => 3
unit = $2.downcase # => year
num *= 12 if unit == "year"
return num
end
raise ArgumentError, "Invalid input"
end
puts to_months("3 Years") # => 36
puts to_months("1 month") # => 1
puts to_months("6months") # => 6
It's not a whole lot more elegant than your method, but perhaps it'll give you an idea or two.

Time-of-day range in Ruby?

I want to know if a time belongs to an schedule or another.
In my case is for calculate if the time is in night schedule or normal schedule.
I have arrived to this solution:
NIGHT = ["21:00", "06:00"]
def night?( date )
date_str = date.strftime( "%H:%M" )
date_str > NIGHT[0] || date_str < NIGHT[1]
end
But I think is not very elegant and also only works for this concrete case and not every time range.
(I've found several similar question is SO but all of them make reference to Date ranges no Time ranges)
Updated
Solution has to work for random time ranges not only for this concrete one. Let's say:
"05:00"-"10:00"
"23:00"-"01:00"
"01:00"-"01:10"
This is actually more or less how I would do it, except maybe a bit more concise:
def night?( date )
!("06:00"..."21:00").include?(date.strftime("%H:%M"))
end
or, if your schedule boundaries can remain on the hour:
def night?(date)
!((6...21).include? date.hour)
end
Note the ... - that means, basically, "day time is hour 6 to hour 21 but not including hour 21".
edit: here is a generic (and sadly much less pithy) solution:
class TimeRange
private
def coerce(time)
time.is_a? String and return time
return time.strftime("%H:%M")
end
public
def initialize(start,finish)
#start = coerce(start)
#finish = coerce(finish)
end
def include?(time)
time = coerce(time)
#start < #finish and return (#start..#finish).include?(time)
return !(#finish..#start).include?(time)
end
end
You can use it almost like a normal Range:
irb(main):013:0> TimeRange.new("02:00","01:00").include?(Time.mktime(2010,04,01,02,30))
=> true
irb(main):014:0> TimeRange.new("02:00","01:00").include?(Time.mktime(2010,04,01,01,30))
=> false
irb(main):015:0> TimeRange.new("01:00","02:00").include?(Time.mktime(2010,04,01,01,30))
=> true
irb(main):016:0> TimeRange.new("01:00","02:00").include?(Time.mktime(2010,04,01,02,30))
=> false
Note, the above class is ignorant about time zones.
In Rails 3.2 it has added Time.all_day and similars as a way of generating date ranges. I think you must see how it works. It may be useful.

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