Remaining seconds until midnight - lua

I'm trying to figure out a good way to get remaining seconds until midnight. I can think of some hacky solution with os.date() but is there a good function for this to go with os.time()?

local dt = os.date("*t")
local remaining_seconds = (dt.hour * -3600 - dt.min * 60 - dt.sec) % 86400

You can exploit the fact that the time and date library does date arithmetic:
dt=os.date("*t")
t0=os.time(dt)
dt.day=dt.day+1
dt.hour=0
dt.min=0
dt.sec=0
remaining_seconds=os.time(dt)-t0

Related

F# - convert time in microsecond to day of the week

I am trying to learn F# and was wondering if i have a json object which has time in microseconds as int. I want to get the day, date and time out of this and was wondering how to do it.
I actually happen to have needed to do this recently. You'll almost certainly want to use the .NET time objects (DateTime, DateTimeOffset, TimeSpan) in some capacity. Here's what I went with:
let TicksPerMicrosecond =
TimeSpan.TicksPerMillisecond / 1000L
let FromUnixTimeMicroseconds (us: int64) =
DateTimeOffset.FromUnixTimeMilliseconds 0L + TimeSpan.FromTicks(us * TicksPerMicrosecond)
From TimeSpan.TicksPerMillisecond we can calculate how many are in a microsecond (if I remember correctly it's 10, but this way it doesn't seem as "magic"). Then I can convert the microseconds value into ticks and add it to the epoch date.
To get the day of the week (assuming the time zone is UTC), you'd just use DateTimeOffset.DayOfWeek.

How to implement a stopwatch in Lua?

How would you make a stopwatch in Lua?
I don't know Codea at all I'm afraid and you will most likely find that there are functions provided by that library for gettime and sleep. However as a pure Lua option (with the proviso that you use luasocket) the following code implements an example that could be built on.
socket = require('socket')
-- Define the stop watch
local start_time
function start()
-- Start the stop watch
start_time = socket.gettime() - 3800
end
function seconds_ellapsed()
-- Return the number of seconds since the stop watch was started
return socket.gettime() - start_time
end
-- As an example run the stop watch indefinately
start()
while true do
-- Get the time ellapsed and convert it to hours, minutes and seconds
ellapsed = seconds_ellapsed()
hours = math.floor(ellapsed / 3600)
minutes = math.floor((ellapsed - (hours * 3600)) / 60)
seconds = math.floor((ellapsed - (hours * 3600) - (minutes * 60)))
-- Print the time ellapsed to the command line
print(hours .. 'h', minutes .. 'm', seconds .. 's')
-- Wait a second between each update
socket.sleep(1)
end
You could look to use os.clock also but Lua has no builtin mechanism for setting the thread to sleep for a period (which was required for my example so I choose to use luasocket). There is a useful article on possible approaches for implementing sleep in lua here: http://lua-users.org/wiki/SleepFunction
Here is a very basic stopwatch, it starts/resets when the user taps the screen. This example shows elapsed minutes and seconds. If you want to count milliseconds, you can use ElapsedTime instead of os.time() and compute the number of hours, minutes etc. yourself instead of os.date(). Also, I don't have my iPad so there may be a bug.
function setup()
fontSize(20)
background(100, 120, 160)
fill(255)
toggle_timer()
end
function toggle_timer()
timer_on = not timer_on
if timer_on then
start = os.time()
end
end
function draw()
if timer_on then
text(os.date("%M:%S", os.difftime(os.time(), start)),
WIDTH / 2, HEIGHT / 2)
end
end
function touched(touch)
if touch.state == BEGAN then
toggle_timer()
end
end

Jenkins job scheduler

How can I set Jenkins to run a job at a particular time?
Like if I'd like to set it to 8:30am every weekday and this is what I could do
H 7 * * 1-5
this randomly picks up 7:35am as running time.
H is a pseudo-random number, based on the hash of the jobname.
When you configured:
H 7
you are telling it:
At 7 o'clock, at random minute, but that same minute very time
Here is the help directly from Jenkins (just click the ? icon)
To allow periodically scheduled tasks to produce even load on the system, the symbol H (for “hash”) should be used wherever possible. For example, using 0 0 * * * for a dozen daily jobs will cause a large spike at midnight. In contrast, using H H * * * would still execute each job once a day, but not all at the same time, better using limited resources.
The H symbol can be used with a range. For example, H H(0-7) * * * means some time between 12:00 AM (midnight) to 7:59 AM. You can also use step intervals with H, with or without ranges.
The H symbol can be thought of as a random value over a range, but it actually is a hash of the job name, not a random function, so that the value remains stable for any given project
If you want it at 8:30 every weekday, then you must specify just that:
30 8 * * 1-5
Take a look at http://www.cronmaker.com/
0 30 8 ? * MON,TUE,WED,THU,FRI *
30 8 * * 1-5
This would start at 8:30am Mon-Fri.
0 and 7 are Sundays.
Not sure what the H does but I am assuming it takes the lower case hex of h and applies 68 which is 35 in decimal... lol. Don't do that.
Following this format:
Minute Hour DayOfMonth DayOfWeek Day
It picks that time because you told it that it can, as imagine you already know:
minute, hour, day of month, month, day of week.
Now you have user H which allows Jenkins to pick at random. So you have told it to run between 7-8 every week day.
Change this to:
30 8 * * 1-5
Hope this helps!

Timecodes in Rails - time or numeric values?

I'm working on a project that stores data on audio tracks and requires the use of timecodes for the start and end points of the track on the audio. I also need to calculate and display the duration of the track. Eg. a track starts at 0:01:30 and finishes at 0:04:12. So its duration is a total of 2 mins and 42 secs.
The trick is that everything needs to be displayed and handled as timecodes, so in the above example the duration needs to be displayed as 0:02:42.
So my question is how you would store the values? The easiest option would be to store the start and end times as Time in the database. Its very easy to calculate the duration and you can utilise the Rails time helpers in the forms. The only painful part is turning the duration back into a time value for display (since if I supply just the number of seconds to strptime it keeps using the current time to fill in the other fields)
The other option that I considered is storing them as numeric values (as the number of seconds). But then I have to write a lot of code to convert them to and from some type of timecode format and I can't use the Rails time helpers.
Is there another idea that I haven't considered? Is there an easy way to calculate and display the duration as a timecode format?
I would store them as seconds or milliseconds. I've been working on a music library manager/audio player in Ruby, and I actually had to write the two methods you would need. It's not that much code:
# Helper method to format a number of milliseconds as a string like
# "1:03:56.555". The only option is :include_milliseconds, true by default. If
# false, milliseconds won't be included in the formatted string.
def format_time(milliseconds, options = {})
ms = milliseconds % 1000
seconds = (milliseconds / 1000) % 60
minutes = (milliseconds / 60000) % 60
hours = milliseconds / 3600000
if ms.zero? || options[:include_milliseconds] == false
ms_string = ""
else
ms_string = ".%03d" % [ms]
end
if hours > 0
"%d:%02d:%02d%s" % [hours, minutes, seconds, ms_string]
else
"%d:%02d%s" % [minutes, seconds, ms_string]
end
end
# Helper method to parse a string like "1:03:56.555" and return the number of
# milliseconds that time length represents.
def parse_time(string)
parts = string.split(":").map(&:to_f)
parts = [0] + parts if parts.length == 2
hours, minutes, seconds = parts
seconds = hours * 3600 + minutes * 60 + seconds
milliseconds = seconds * 1000
milliseconds.to_i
end
It's written for milliseconds, and would be a lot simpler if it was changed to work with seconds.

How do I get the number of seconds between two DateTimes in Ruby on Rails

I've got code that does time tracking for employees. It creates a counter to show the employee how long they have been clocked in for.
This is the current code:
start_time = Time.parse(self.settings.first_clock_in)
total_seconds = Time.now - start_time
hours = (total_seconds/ 3600).to_i
minutes = ((total_seconds % 3600) / 60).to_i
seconds = ((total_seconds % 3600) % 60).to_i
This works fine. But because Time is limited to the range of 1970 - 2038 we are trying to replace all Time uses with DateTimes. I can't figure out how to get the number of seconds between two DateTimes. Subtracting them yields a Rational which I don't know how to interpret, whereas subtracting Times yields the difference in seconds.
NOTE: Since Ruby 1.9.2, the hard limit of Time is removed. However, Time is optimized for values between 1823-11-12 and 2116-02-20.
Subtracting two DateTimes returns the elapsed time in days, so you could just do:
elapsed_seconds = ((end_time - start_time) * 24 * 60 * 60).to_i
Or, more readably:
diff = datetime_1 - datetime_2
diff * 1.days # => difference in seconds; requires Ruby on Rails
Note, what you or some other searchers might really be looking for is this:
diff = datetime_1 - datetime_2
Date.day_fraction_to_time(diff) # => [h, m, s, frac_s]
You can convert them to floats with to_f, though this will incur the usual loss of precision associated with floats. If you're just casting to an integer for whole seconds it shouldn't be big enough to be a worry.
The results are in seconds:
>> end_time.to_f - start_time.to_f
=> 7.39954495429993
>> (end_time.to_f - start_time.to_f).to_i
=> 7
Otherwise, you could look at using to_formatted_s on the DateTime object and seeing if you can coax the output into something the Decimal class will accept, or just formatting it as plain Unix time as a string and calling to_i on that.
Others incorrectly rely on fractions or helper functions. It's much simpler than that. DateTime itself is integer underneath. Here's the Ruby way:
stop.to_i - start.to_i
Example:
start = Time.now
=> 2016-06-21 14:55:36 -0700
stop = start + 5.seconds
=> 2016-06-21 14:55:41 -0700
stop.to_i - start.to_i
=> 5
I am using ruby-2.1.4 and for me the following worked
Time.now - Time.new(2014,11,05,17,30,0)
gave me the time difference in seconds
reference: ruby doc
there's a method made for that:
Time.now.minus_with_coercion(10.seconds.ago)
equals 10.
Source: http://apidock.com/rails/Time/minus_with_coercion
Hope I helped.
Define a Ruby function like this,
def time_diff(start_time, end_time)
seconds_diff = (start_time - end_time).to_i.abs
days = seconds_diff / 86400
seconds_diff -= days * 86400
hours = seconds_diff / 3600
seconds_diff -= hours * 3600
minutes = seconds_diff / 60
seconds_diff -= minutes * 60
seconds = seconds_diff
"#{days} Days #{hours} Hrs #{minutes} Min #{seconds} Sec"
end
And Call this function,
time_diff(Time.now, Time.now-4.days-2.hours-1.minutes-53.seconds)

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