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Get value from table/matrix based on common attribute

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John Taylor
John Taylor on 26 Feb 2021
Edited: John Taylor on 2 Mar 2021
I have two tables, A with informtions about people and where they live, B informations about cities. Several people can live in the same city. How can I add columns in A with the informations in B (city name, country) based on the Citycode without a loop?
A = table('Name','First','Citycode')
B = table('Citycode','CityName','Country')
A = ['Smith' 'John' '1001';
'Taylor' 'James' '1004';
'Thatcher' 'Mary' '1001']
B = ['1001' 'New York' 'USA';
'1002' 'London' 'UK';
'1004' 'Madrid' 'Spain']
  1 Comment
Rik on 26 Feb 2021
Your syntax will not result in two tables. Please modify your code to reflect the actual data type of your variables.
I expect ismember will be helpful, but without your actual input data, I can't write the code for you.

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Accepted Answer

Hernia Baby
Hernia Baby on 26 Feb 2021
% input data
A = {'Smith' 'John' '1001';
'Taylor' 'James' '1004';
'Thatcher' 'Mary' '1001'};
B = {'1001' 'New York' 'USA';
'1002' 'London' 'UK';
'1004' 'Madrid' 'Spain'};
A_t = cell2table(A,'VariableNames',{'Name','First','Citycode'});
B_t = cell2table(B,'VariableNames',{'Citycode','CityName','Country'});
% join
T = innerjoin(A_t,B_t)
T =
3×5 table
Name First Citycode CityName Country
____________ _________ ________ ____________ _________
{'Smith' } {'John' } {'1001'} {'New York'} {'USA' }
{'Thatcher'} {'Mary' } {'1001'} {'New York'} {'USA' }
{'Taylor' } {'James'} {'1004'} {'Madrid' } {'Spain'}
  1 Comment
John Taylor
John Taylor on 2 Mar 2021
Thanks, in my case, there are people who do not have a citycode assigned and disappear with the innerjoin command (which only keeps the matching citycodes). I rather used:
T = outerjoin(A_t,B_t,'Type','left')
So, my table T has the same number of rows as A_t, and there's no loss of information.

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