How can I separate individual years from a timetable?

Hi!

I have one table that contains 764 rows with different year's data point from 1984 to 2022. For example, row 1 to 8 are for 1984, row 9 to 14 are for 1985, row 15 to 24 are for 1986 and so on.

Can anyone please tell me how to create a cell array where I can have the indices for the individual year?

i.e., {year_list} = {[1:8];[9:14];[15:24],....} etc.

I have added the table in this question. Any feedback will be greatly appreciated!!

Answer 1

[Stephen23]

S = load('DateStamp.mat')

S = struct with fields:
    DateStamp: [764×3 table]

T = S.DateStamp

T = 764×3 table
       date       x_CloudCover       landsat   
    __________    ____________    _____________

    1984-05-02        0.12        {'landsat_5'}
    1984-06-03       18.49        {'landsat_5'}
    1984-06-19           0        {'landsat_5'}
    1984-09-23        1.49        {'landsat_5'}
    1984-10-09        47.1        {'landsat_5'}
    1984-10-25        7.27        {'landsat_5'}
    1984-11-10       46.36        {'landsat_5'}
    1984-11-26        0.08        {'landsat_5'}
    1985-01-29        0.11        {'landsat_5'}
    1985-04-19       71.61        {'landsat_5'}
    1985-06-22        1.53        {'landsat_5'}
    1985-08-09           0        {'landsat_5'}
    1985-10-12           0        {'landsat_5'}
    1985-10-28           0        {'landsat_5'}
    1986-01-16       16.37        {'landsat_5'}
    1986-02-01       43.73        {'landsat_5'}

[G,Y] = findgroups(T.date.Year);
X = arrayfun(@(x)find(x==G), 1:max(G), 'uni',0);

These are the years:

Y

Y = 39×1

1984 1985 1986 1987 1988 1989 1990 1991 1992 1993

and the corresponding indices:

X

X = 1×39 cell array
    {8×1 double}    {6×1 double}    {10×1 double}    {12×1 double}    {12×1 double}    {14×1 double}    {9×1 double}    {12×1 double}    {14×1 double}    {14×1 double}    {12×1 double}    {14×1 double}    {8×1 double}    {9×1 double}    {11×1 double}    {25×1 double}    {23×1 double}    {26×1 double}    {24×1 double}    {25×1 double}    {23×1 double}    {28×1 double}    {25×1 double}    {24×1 double}    {29×1 double}    {22×1 double}    {24×1 double}    {23×1 double}    {10×1 double}    {23×1 double}    {28×1 double}    {30×1 double}    {32×1 double}    {24×1 double}    {24×1 double}    {30×1 double}    {26×1 double}    {28×1 double}    {23×1 double}

X{1:3}

ans = 8×1

1 2 3 4 5 6 7 8

ans = 6×1

9 10 11 12 13 14

ans = 10×1

15 16 17 18 19 20 21 22 23 24

See also:

https://www.mathworks.com/help/matlab/matlab_prog/grouping-variables-for-splitting-data.html

https://www.mathworks.com/help/matlab/matlab_prog/perform-calculations-by-group-in-table.html

[Ashfaq Ahmed]

Hi! Thank you @Stephen23. This is a cool way to list the indices, and I didn't know about it. But that is not what I was looking for. I want to prepare the count for individual years as I mentioned in the question -

i.e., {year_list} = {[1:8];[9:14];[15:24],....} etc.

Because I will have to feed the number of the arrays in my later calculation. Any suggestion from you will be very helpful in thi regard!

[Ashfaq Ahmed]

Excellent! Thanks

[Ashfaq Ahmed]

Hi @Stephen23, can you please give me an idea on how can I show an observation count for individual year?

For example, 1984 had 8 observations, 1985 has 6, 1987 has 10 and so on. I am imagining a histogram where X axis will represent the year and Y-axis is for observation frequency. But I am not sure if it is possible to plot. Then I might have to look other way.

[Stephen23]

S = load('DateStamp.mat');
T = S.DateStamp

T = 764×3 table
       date       x_CloudCover       landsat   
    __________    ____________    _____________

    1984-05-02        0.12        {'landsat_5'}
    1984-06-03       18.49        {'landsat_5'}
    1984-06-19           0        {'landsat_5'}
    1984-09-23        1.49        {'landsat_5'}
    1984-10-09        47.1        {'landsat_5'}
    1984-10-25        7.27        {'landsat_5'}
    1984-11-10       46.36        {'landsat_5'}
    1984-11-26        0.08        {'landsat_5'}
    1985-01-29        0.11        {'landsat_5'}
    1985-04-19       71.61        {'landsat_5'}
    1985-06-22        1.53        {'landsat_5'}
    1985-08-09           0        {'landsat_5'}
    1985-10-12           0        {'landsat_5'}
    1985-10-28           0        {'landsat_5'}
    1986-01-16       16.37        {'landsat_5'}
    1986-02-01       43.73        {'landsat_5'}

[G,Y] = findgroups(T.date.Year);
N = accumarray(G,ones(size(G)));
bar(Y,N)