Return a value from a table

Hello,

I have a table of annual quarters as row names and the dates those quarters began as a variable. I'm trying to create a command where given a quarter (R) I can lookup the quarter start date. I've read the documentation and searched for answers here, but am very lost so I'd appreciate any help!

Quarter = {'Q12019'; 'Q22019'; 'Q32019'; 'Q42019'; 'Q12020'; 'Q22020'; 'Q32020'; 'Q42020'};
QuarterStartDate = ['2019-01-01'; '2019-04-01'; '2019-07-01'; '2019-10-01'; '2020-01-01'; '2020-04-01'; '2020-07-01'; '2020-10-01'];

T = table(QuarterStartDate, 'RowNames', Quarter);
R = 'Q32019';
S = T(Quarter == 'R')

I was able to do something similar earlier that worked, but that was using numbers rather than characters. I tried doing the same thing, but that didn't work.

C = [ .80 ; .85 ; .90 ; .95];
P = [.55 ; .49 ; .44 ; .44];

T = table(C, P);
R = 0.95;
S = T{C == R, 2};

Thanks!

[dpb]

Help us out by attaching a (smallish) section of the table as .mat file...

[Ivan Glinski]

Just attached to my post! I just ran the first three lines of the code I shared.

[Walter Roberson]

S = T(strcmp(T.Quarter,'R').QuarterStartDate;

[Ivan Glinski]

Thanks for your help!

After adding a parenthesis at the end to close the command around T, I get an error:

"Unrecognized variable name 'Quarter'."

Quarter is the row name, not a variable. If I change it so that Quarter is a variable in the table, I get the following error:

"Error: Functions cannot be indexed using {} or . indexing."

[Image Analyst]

Try T.QuarterStartDate instead of T.Quarter.

Answer 1

[Stephan]

Quarter = {'Q12019'; 'Q22019'; 'Q32019'; 'Q42019'; 'Q12020'; 'Q22020'; 'Q32020'; 'Q42020'};
QuarterStartDate = ['2019-01-01'; '2019-04-01'; '2019-07-01'; '2019-10-01'; '2020-01-01'; '2020-04-01'; '2020-07-01'; '2020-10-01'];
T = table(QuarterStartDate, 'RowNames', Quarter);
R = 'Q32019';
S = T(R,:)

results in:

S =

  table

              QuarterStartDate
              ________________

    Q32019       2019-07-01

if you need only the content use curly braces:

S = T{R,:}
    
S =

    '2019-07-01'

[Ivan Glinski]

It works, thank you!! I sort of can't believe the solution was this simple, but I'm still learning to think in Matlab terms.