Finding a variable in a large table

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George 2022-12-8

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评论： Voss 2022-12-9

I'm quite a novice to MATLAB so apologies for any language I may use which may be confusing

I have a 2570x16 sized table, which relates to data about every UK train station, i.e. usage statistics, I have written a menu function which allows the selected station to become a string, what do I need to do so that the Station can be found in the name column, and then this can be used to recall the other 15 parts of data about the station?

Many thanks

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Answer 1

Voss 2022-12-8

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% a table with station names and other info:
t = table(["Picadilly Circus"; "St. John's Wood"; "Cockfosters"],rand(3,1),rand(3,1), ...
    'VariableNames',{'name' 'other info 1' 'other info 2'})
t = 3×3 table
           name           other info 1    other info 2
    __________________    ____________    ____________

    "Picadilly Circus"      0.14357         0.81944   
    "St. John's Wood"        0.2586         0.93962   
    "Cockfosters"           0.47828         0.34349   
% the station you want to know about:
station = "Cockfosters";
% get all the info about that station:
result = t(strcmp(t.name,station),:) % result is a table with one row
result = 1×3 table
        name         other info 1    other info 2
    _____________    ____________    ____________

    "Cockfosters"      0.47828         0.34349   
% and/or get just the "other info" for that station:
% (this assumes 'name' is the first column of the table)
result = t{strcmp(t.name,station),2:end} % result is a numeric array in this case
result = 1×2
    0.4783    0.3435

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George 2022-12-9

Thnak you!

Voss 2022-12-9

You're welcome!

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Answer 2

Jon 2022-12-8

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编辑：Jon 2022-12-8

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Here's a simple example, which I think you could extend to your situation

% make an example table
name = {'fish','cat','dog','cat','mouse','mouse','fish','cat'}'
weight = [0.8, 1.3, 2.2, 1.1, 0.2, 0.3, 0.9, 1.4]'
bodyLength = [102,503,608, 429,15,18, 154,496]'
T = table(name,weight,bodyLength)
% get the weights and lengths of all of the cats
idl = strcmp('cat',T.name);
Tcat = T(idl,:) % a table with just cat data
% or if you just want the weight of the fish
idl = strcmp('fish',T.name);
wFish = T.weight(idl)

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Answer 3

Bora Eryilmaz 2022-12-8

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编辑：Bora Eryilmaz 2022-12-8

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% Create a table
T = table;
T.Name = ["London"; "Paris"];
T.Data1 = {15; 20};
T.Data2 = {-1; 2};
T
T = 2×3 table
      Name      Data1     Data2 
    ________    ______    ______

    "London"    {[15]}    {[-1]}
    "Paris"     {[20]}    {[ 2]}
% Find index of Name
I = strcmp(T.Name, 'Paris');
% Find data for that Name
T{I,:}
ans = 1×3 string array
    "Paris"    "20"    "2"
% or, extract data as its own 1-row table
T(I,:)
ans = 1×3 table
     Name      Data1     Data2
    _______    ______    _____

    "Paris"    {[20]}    {[2]}