Make histogram for array of datetimes

I have a datetime array:

trigDatetime = 

  1273×1 datetime array

   2024-04-30 01:15:34
   2024-04-30 01:19:27
   2024-04-30 02:20:49
   2024-04-30 03:48:50
   2024-04-30 03:49:49

How can I calculate the frequency of occurence between two dates for a bin width of an integer number of hours (1, 2, 3, 4, 6 or 12)?

Answer 1

[Steven Lord]

Let's make some sample dates and times.

n = 10;
T = datetime('today');
d = T + ...
    hours(randi([-24, 24], n, 1)) + ...
    minutes(randi(60, n, 1)) + ...
    seconds(randi(60, n, 1))

d = 10x1 datetime array
   15-May-2024 13:09:38
   16-May-2024 01:12:13
   16-May-2024 21:27:33
   15-May-2024 17:34:09
   15-May-2024 12:54:39
   16-May-2024 18:39:16
   16-May-2024 20:18:13
   16-May-2024 21:40:51
   15-May-2024 14:15:30
   16-May-2024 09:22:37

Now make a histogram.

histogram(d, BinWidth = hours(1))

By default this isn't going to show enough ticks on the X axis for my taste. This adds a few more.

xticks(T + hours(-24:4:24))

If you just want the counts, not the pictures, see histcounts.

[dormant]

Brilliant, thanks.

Answer 2

[William Rose]

@dormant, I am switching my comment to be an answer which is what I had intended.

First, let's create an array of 1273 random date times in the first week of April:

dt0=datetime(['1-Apr-2024']);              % start time
D=duration(0,0,60*60*24*7*rand(1273,1));    % 1273 random durations up to 1 week
dt=dt0+D;           % random date times startng at dt0
fprintf ('Datetime range: %s to %s.\n',min(dt),max(dt))

Datetime range: 01-Apr-2024 00:06:04 to 07-Apr-2024 23:58:53.

Now make a histogram with 12 hour bin width

histogram(dt,BinWidth=duration(12,0,0))

You can adjust for bin width=1, 3, 6 hours. Good luck.

[dormant]

Thanks