How to call a specific element of a table

5 vues (au cours des 30 derniers jours)
Zeynab Mousavikhamene
Zeynab Mousavikhamene le 29 Août 2019
Modifié(e) : Andrei Bobrov le 30 Août 2019
I want to
find the "radius" in which "time" is 2 and p"erhexagon" is 2.1667. There might be more than one radius that matches this criteria.
Any suggestion?
  2 commentaires
KALYAN ACHARJYA
KALYAN ACHARJYA le 29 Août 2019
Modifié(e) : KALYAN ACHARJYA le 29 Août 2019
Have you check here?
Still unable to resolve it, please attach the table.
madhan ravi
madhan ravi le 29 Août 2019
Learn to attach data as .mat file as shown by Andrei below, attaching a screenshot is useless!

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Réponse acceptée

Adam Danz
Adam Danz le 29 Août 2019
Modifié(e) : Adam Danz le 29 Août 2019
Assuming your table is named "T",
% find the rows where time equals 2 and perhexagon equals exactly 2.1667
rowidx = T.time == 2 & T.perhexagon == 2.1667;
% use the row index to get the chosen radii
chosenRads = T.radius(rowidx);
Note that if you have trouble matching the floating point decimals, you may have to build in a tolerance instead of requiring an exact match. Example below.
% Define tolerance
tol = 0.001; %accepted if perhexagon value is +/-tol from target
% find the rows where time equals 2 and perhexagon equals exactly 2.1667
rowidx = T.time == 2 & abs(T.perhexagon - 2.1667)<tol;
  2 commentaires
Zeynab Mousavikhamene
Zeynab Mousavikhamene le 29 Août 2019
Modifié(e) : Zeynab Mousavikhamene le 29 Août 2019
Thanks.
I tried:
% find the rows where time equals 2 and perhexagon equals exactly 2.1667
rowidx = Acc_cellcount.time == 2 & Acc_cellcount.perhexagon == 2.1667;
% use the row index to get the chosen radii
chosenRads = Acc_cellcount.radius(rowidx);
and it came out:
chosenRads =
0×1 empty double column vector
Adam Danz
Adam Danz le 29 Août 2019
This is where my "note" comes in at the end of my answer. Your "perhexagon" values aren't really 2.1667. Those are just the first 4 decimal places. So you need to build in a tolerance. For example, accept any rows where perhexagon is within 0.0001 within the target value. I'll update my answer.

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Plus de réponses (1)

Andrei Bobrov
Andrei Bobrov le 29 Août 2019
Modifié(e) : Andrei Bobrov le 29 Août 2019
load data.mat
lo = ismembertol(T{:,{'time','perhexagon'}},[2,2.1667],'ByRows',true,...
'DataScale',[1 .00001]);
out_radius = T.radius(lo);
  2 commentaires
Zeynab Mousavikhamene
Zeynab Mousavikhamene le 29 Août 2019
Modifié(e) : Zeynab Mousavikhamene le 29 Août 2019
Got this error:
Error using load
Unable to read file 'data.mat'. No such file or directory.
I run for the second time without "Error using load" and I got :
"out_radius =
0×1 empty double column vector"
Tried multiple 'DataScales': [1 .001] or [1 .1] or [1]
all gave empty out_radius.
Andrei Bobrov
Andrei Bobrov le 30 Août 2019
Modifié(e) : Andrei Bobrov le 30 Août 2019
You do not know how to download, sorry.
Exsample my laptop with Ubuntu (I from Russia :) ):
>> load '/home/andrei/Загрузки/data.mat'
>> lo = ismembertol(T{:,{'time','perhexagon'}},...
[2,2.1667],'ByRows',true,'DataScale',[1 .00001]);
out_radius = T.radius(lo)
out_radius =
1
2
>>

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