Borrar filtros
Borrar filtros

How to filter table rows according different conditions?

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Giuseppe
Giuseppe el 3 de Oct. de 2022
Respondida: dpb el 3 de Oct. de 2022
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

Respuesta aceptada

Steven Lord
Steven Lord el 3 de Oct. de 2022
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

Más respuestas (1)

dpb
dpb el 3 de Oct. de 2022
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.

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