removing rows from a timetable

I want to remove the first year (1985) of data (12 rows as it is monthly data) from a timetable matrix. what is the easiest way to do this?

Answer 1

[madhan ravi]

load combined_observed_vs_sim_timetable
combined_data(1 : 12, :) = [ ]

combined_data = 168×22 timetable
      Date      Observed_Rio_Branco    Observed_Floriano_Peixoto    Observed_Fazenda_Borangaba    Observed_Bacaba    Observed_Aruma_Jusante    Observed_Canutama    Observed_Labrea    Observed_Seringal_Fortaleza    Observed_Valparaiso_Montante    Observed_Seringal_da_Caridade    Observed_Manoel_Urbano    Simulated_Rio_Branco    Simulated_Floriano_Peixoto    Simulated_Fazenda_Borangaba    Simulated_Bacaba    Simulated_Aruma_Jusante    Simulated_Canutama    Simulated_Labrea    Simulated_Seringal_Fortaleza    Simulated_Valparaiso_Montante    Simulated_Seringal_Da_Caridade    Simulated_Manoel_Urbano
    ________    ___________________    _________________________    __________________________    _______________    ______________________    _________________    _______________    ___________________________    ____________________________    _____________________________    ______________________    ____________________    __________________________    ___________________________    ________________    _______________________    __________________    ________________    ____________________________    _____________________________    ______________________________    _______________________

    Jan-1986            1017                    969.63                        1349.9                    1802                 6968.7                  10561              9772.3                   6905.8                          4304.6                          2888.9                        2076.7                   559.83                     732.66                        1045.9                    1872.9                  10375                     5828               5576.8                    4237.3                            2743                            1872.5                        1383.7         
    Feb-1986          1230.6                    1830.1                          1724                  2647.1                 8423.2                  12426               10847                   8811.1                          5477.1                          3967.5                        2965.6                   1018.1                       1276                        1290.3                      1979                  12589                   8103.4               7833.7                    6166.8                          4248.9                            2778.7                        2047.2         
    Mar-1986          967.34                      1840                        1709.1                  2929.3                  13547                  12834               11064                   9360.4                          5506.5                          3509.2                        2897.9                     1129                     1428.7                        1258.9                    1841.9                  13774                   9018.3                 8723                    6927.6                          4991.6                            3345.2                        2442.8         
    Apr-1986          806.47                      1263                        1877.3                    2846                  17404                  12920               11184                    10054                          6061.8                          2886.3                        1916.9                    797.7                     1075.2                        978.77                      1824                  12595                   7795.5                 7482                    5710.9                            4088                            2808.2                        1915.8         
    May-1986          293.87                    626.74                        1151.5                  2668.3                  19464                  12606               10787                   6231.6                          2891.5                          1380.9                        721.38                   415.34                     635.24                        491.36                    1402.7                 9157.1                   5217.9               4937.3                    3443.1                          2436.3                            1637.9                        930.86         
    Jun-1986          113.97                    290.89                        310.43                  2173.6                  19749                 9329.1              6656.8                   2421.8                          1024.4                          494.37                        397.73                   279.31                     456.66                        222.99                    751.22                 6395.5                   3686.3               3456.4                    2237.3                          1596.2                            1007.3                        437.98         
    Jul-1986          83.097                    134.22                        196.55                  1146.7                  17103                 3293.9                2458                     1166                           398.3                          171.84                        114.43                   215.85                     360.92                        115.09                    344.92                   4721                   2805.1               2617.9                      1618                          1159.4                               690                        225.64         
    Aug-1986          78.416                    129.61                        129.74                  562.03                  11957                 1839.4              1575.4                   895.49                          306.07                          125.81                        89.861                   174.67                     294.66                        62.785                    174.53                 3696.4                   2223.8               2068.6                    1238.8                           890.4                            505.66                        122.85         
    Sep-1986          76.319                    135.29                        156.27                  571.07                 6949.5                 1666.1              1413.4                   867.31                          353.05                          156.67                        109.37                   144.07                     245.14                        35.887                    94.731                 3019.4                   1823.4               1692.5                    990.71                          712.78                             391.4                        70.092         
    Oct-1986          100.75                     118.7                        200.94                  549.16                 5145.5                   1742              1581.5                   993.03                          526.13                          334.39                        311.02                   119.42                     205.91                        22.724                    63.454                 2661.8                   1534.2               1421.6                    818.02                          586.69                            315.16                        41.187         
    Nov-1986          132.78                    284.27                         265.8                   696.7                 5852.8                 1881.9              1790.1                   1053.2                          702.09                          678.13                        368.47                   185.98                     278.49                        269.27                    445.67                 3815.9                   2038.1               1938.4                    1381.7                          908.01                            561.87                         287.4         
    Dec-1986           311.8                    683.23                        809.84                  1362.1                 7161.6                 5274.3              5180.8                   4164.3                            2837                          2159.6                        1194.1                   361.42                     488.24                        652.51                    1010.2                 6179.4                   3637.2               3516.5                    2807.2                          1873.1                              1293                        926.36         
    Jan-1987          703.97                    1284.5                        1333.1                  1768.1                 8527.8                   9187              8415.3                   6284.7                          4345.4                          2976.5                        1731.3                   402.92                     556.37                         908.3                    1425.5                 7716.6                   4609.4               4469.3                    3545.9                          2268.8                            1599.5                        1169.7         
    Feb-1987          540.83                    1293.7                          1632                  2545.4                  10767                  11981               10684                   7222.1                          3844.9                            1940                        1067.2                   607.64                     818.61                        1401.3                    1649.1                 9676.1                   6120.9               5979.9                    4844.7                          2908.3                            1932.9                        1373.7         
    Mar-1987          321.32                    634.69                        1605.3                  3037.1                  14944                  12625               10880                   6217.7                          2440.1                          1432.5                        716.73                   916.95                     1208.1                        1850.8                      1849                  12269                   8163.1               7995.2                    6502.2                          3850.3                            2418.7                        1628.5         
    Apr-1987           396.5                    514.03                        1241.1                  2816.8                  18866                  12031                9932                   4864.4                          2224.2                          1562.3                        1072.1                   756.44                     1064.3                        1429.1                    1946.1                  12403                   7682.5               7459.9                    5666.6                          3364.9                            2059.7                        1241.9         

Answer 2

[Steven Lord]

Do you want to remove the data from 1985 from your timetable or do you want to remove the first twelve rows from it? In this particular case it appears that those two operations would give the same result, but that may not always be the case.

v = (1:10).';
dt = datetime('now', 'Format', 'h:mm:ss a') + minutes(randi([30 90], 10, 1));
tt = timetable(dt, v)

tt = 10×1 timetable
        dt         v 
    ___________    __

    10:40:38 PM     1
    9:50:38 PM      2
    10:24:38 PM     3
    10:35:38 PM     4
    10:28:38 PM     5
    9:47:38 PM      6
    10:38:38 PM     7
    10:09:38 PM     8
    10:05:38 PM     9
    10:31:38 PM    10

Let's remove every row that takes place before 10 PM.

whatHour = hour(tt.dt);
tt(whatHour < 22, :) = []

tt = 8×1 timetable
        dt         v 
    ___________    __

    10:40:38 PM     1
    10:24:38 PM     3
    10:35:38 PM     4
    10:28:38 PM     5
    10:38:38 PM     7
    10:09:38 PM     8
    10:05:38 PM     9
    10:31:38 PM    10

For your application you would want to use the year function.

[Elizabeth Lees]

thanks for the reply, and yes agreed this would not and may not always be the same. However in my dataset the datetime (which you express as dt) is already present in the timetable when I created it. Therefore I'm unsure how the remaining script you've suggested would work - currently I'm recieving the error message 'Input data must be a real, numeric array.' when using the years function and then also 'Error: Incorrect use of '=' operator. To assign a value to a variable, use '='. To compare values for equality, use '=='.' when using the second line of code. When if not defining it to equal a new table I still get an error message stating 'Undefined function or variable 'WhatYear'.' This is how I've formatted by script for reference:

whatYear =years(combined_data)
test = combined_data(WhatYear < 1986, :)=[];

[Steven Lord]

whatYear =years(combined_data)

combined_data appears to be your timetable array. You need to pass its times into years. Note when I called hours I called it not with tt as input but tt.dt, which is the datetime part of tt.

test = combined_data(WhatYear < 1986, :)=[];

Assign to test or delete rows from combined_data, not both simultaneously.

% either

% keep certain rows and make a copy
test = combined_data(WhatYear >= 1986, :);

% or delete rows and don't make a copy 
combined_data(WhatYear < 1986, :)=[];

% or make a copy and then delete rows from the copy
test = combined_data;
test(WhatYear < 1986, :)=[];