Counting days by month

hi,

i have a 100x11 char array with dates (e.g. '03-Jan-2006'). how can i create an array with the number of days in each unique month that appear in my date array. (e.g. if i have two days in january 2006, then i want it to return 2). any help would be appreciated. thx in advance.

DB

Answer 1

[Andrei Bobrov]

Here A - your array "100x11 char array with dates (e.g. '03-Jan-2006')"

 z = datetime(A);
 T = table(datetime(z,'F','MMM-uuuu'),eomday(year(z),month(z)),'v',{'date','days'});

[dan berkowitz]

close, but not quite. this give the number of days in each calendar month. what i'm trying to get is the number of days for each month in my datetime vector (i.e. if i have two days in january 2006, then i want it to return 2). ideally, i'd like a column with each unique month then number of days in my datetime vector that are in that month, e.g. [january 2006, 2].

[Andrei Bobrov]

[y,m] = ymd(z);
[a,~,c] = unique([y,m],'rows');
T_out = table(datetime(a(:,1),a(:,2),1,'f','MMM-uuuu'),...
                                             accumarray(c,1),'v',{'date','days'});

[dan berkowitz]

Thank you! I didn't know about the ymd function! Appreciate your help.

[Andrei Bobrov]

[y,m] = ymd(z);

or

[y,m] = datevec(z);

Answer 2

[KL]

It's better to change your char array into datetime vector

 dt_array = datetime(char_array,'InputFormat','dd-MMM-yyyy')

and then you can use

 numOfDays = nnz(dt_array.Month==your_month)