How to filter table rows according different conditions?

Hi guys, I have a large table with 4480 rows and I need to filter them to mantain only rows matching a given condition.

clear all; close all; clc;

%Data import
file_name = 'NHATS_data.csv';

NHATS_table = readtable(file_name,"VariableNamingRule","preserve");

filt_cnd = strcmp(NHATS_table.Object,'(2020 HO5)');
% Other conditons on object names:
% ||...  || (2021 GM1) || (2021 LF6) || (2020 CD3) 
%     || (2020 FA1) || (2020 HF4) || (2020 MU1) || (2020 WY) 
% || (2021 AK5) || (2021 RZ3) || (2021 RG12) || (2022 BY39)

%Data filtering
NHATS_table_filtered = NHATS_table(filt_cnd,:)

NHATS_table_filtered = 1×11 table
        Object        Orbit ID    H (mag)    Estimated Diameter (m)    OCC    Min. delta-V [delta-V, dur.] (km/s), (d)    Min. Duration [delta-V, dur.] (km/s), (d)    Viable Trajectories    Next Optical Opportunity (yyyy-mm [Vp])    Next Goldstone Radar Opportunity (yyyy-mm [SNR])       Var11    
    ______________    ________    _______    ______________________    ___    ________________________________________    _________________________________________    ___________________    _______________________________________    ________________________________________________    ____________

    {'(2020 HO5)'}       5         28.5           {'3.5 - 16'}          4                  {'3.874, 362'}                              {'11.997, 26'}                      1.0614e+06                        {'none'}                                        {'none'}                        {'bK20H05O'}

I need to mantain all the rows that contains the objects whose names are the commentend ones. Up to now I managed to impose the condition on a single object name, can you help me to code in way that I can impost contemproary all the conditons?

Thanks in advance

Answer 1

[Steven Lord]

You can do this using ismember or (depending on your conditions) some of the string processing functions like matches, contains, startsWith, endsWith, etc.) Let's make a sample table.

load patients
T = table(LastName, Age);

Let's look for all patients whose names are Smith or Jones. For this I'll use ismember.

T(ismember(T.LastName, ["Smith", "Jones"]), :)

ans = 2×2 table
    LastName     Age
    _________    ___

    {'Smith'}    38 
    {'Jones'}    40 

How about all patients whose names start with J?

T(startsWith(T.LastName, 'J'), :)

ans = 5×2 table
     LastName      Age
    ___________    ___

    {'Johnson'}    43 
    {'Jones'  }    40 
    {'Jackson'}    25 
    {'James'  }    25 
    {'Jenkins'}    28 

Starts with B or ends with r? For this we need to combine startsWith and endsWith.

T(startsWith(T.LastName, 'B') | endsWith(T.LastName, 'r'), :)

ans = 18×2 table
     LastName      Age
    ___________    ___

    {'Brown'  }    49 
    {'Miller' }    33 
    {'Taylor' }    31 
    {'Walker' }    28 
    {'Baker'  }    44 
    {'Carter' }    38 
    {'Turner' }    37 
    {'Parker' }    30 
    {'Bell'   }    45 
    {'Bailey' }    38 
    {'Cooper' }    28 
    {'Brooks' }    39 
    {'Bennett'}    35 
    {'Barnes' }    42 
    {'Butler' }    38 
    {'Foster' }    30 

Answer 2

[dpb]

NHATS_table = readtable(file_name,"VariableNamingRule","preserve");
NHATS_table.Object=categorical(NHATS_table.Object);     % convert to categorical (several others probably should be as well...)
WANTLIST={'(2020 HO5)','(2021 GM1)','(2021 LF6)','(2020 CD3)','(2020 FA1)','(2020 HF4)','(2020 MU1)','(2020 WY)'}; 

NHATS_table_filtered = NHATS_table(ismember(NHATS_table.Object,WANTLIST),:);

NB: It may not be necessary to actually create the second table but use groupfilter with the given group.