xlsread unable to import data or sorts the imported data. please advice.

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nitin arora
nitin arora on 17 Apr 2015
Edited: nitin arora on 27 Apr 2015
I am trying to read x and y coordinates into separate arrays, say x and y. Sometimes,
  1. xlsread does not read any value from the specified column
  2. xlsread grabs the value from the column but sorts them resulting in mismatch between x and y coordinates
I am not sure whats the way around? Is it a bug? It happens sometimes only.
  1 Comment
Image Analyst
Image Analyst on 17 Apr 2015
It could be a weird entry in your Excel cell. Who knows? Not us, because you didn't attach a workbook for which it fails for us to check.

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Accepted Answer

Ken Atwell
Ken Atwell on 18 Apr 2015
Nitin, I was able to load this 20 times in a row without issue. But, I am on Mac, which uses quite a different code path than a Windows computer (you didn't say what OS you are using), so we may not be making much of a comparison.
Try not to have Excel running on your computer at the same time you run this code. I've heard claims, but never personally verified, that reliability drops when Excel is being used both as a Desktop application and Automation server.
This is a stab in the dark, but try loading the spreadsheet in one command, passing 'basic' as the fourth argument to xlsread. This will cause MATLAB to read the file with its own reader, instead of bridging to Excel using Automation to do the read. The assign the columns to individual variable. Maybe there is some kind of timing issue with running xlsread in rapid succession? That code would look like:
foo=xlsread('test1.xlsx','Sheet1','','basic');
ya=foo(:,1);
za=foo(:,2);
yb=foo(:,28);
zb=foo(:,29);
  1 Comment
nitin arora
nitin arora on 27 Apr 2015
Thanks Ken, I did not get into the problem of xlsread sorting my data again. you are right that excel was open when I was trying to import the data from excel into matlab.
Thanks image analyst.

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More Answers (1)

Ken Atwell
Ken Atwell on 17 Apr 2015
I can answer question #2, I think. If you have two separate variables and you sort one, then, yes, the two variables will now be out of sync. To can overcome this by:
  1. Use a container like a table that keeps columns of related data synched.
  2. Use the second output of sort and apply that to the second array:
[X, I] = sort(X);
Y = Y(I);
  6 Comments
nitin arora
nitin arora on 17 Apr 2015
Sorry. Please find ignore the previous message and code. Yes, xlsread() sorted my data yesterday without using any sort command. Attached code is not sorting the data today but it was doing that yesterday. After restarting the desktop, the problem went away.
If I saw this sorting behavior again, I will let you know.However, attached code is unable to pick some columns. Please run the code several times. Sometimes, the value gets picked but sometimes it does not. Seems like a bug.
clc
clear all
ya = xlsread('test1.xlsx','Sheet1','A3:A7'); za = xlsread('test1.xlsx','Sheet1','B3:B7'); yb = xlsread('test1.xlsx','Sheet1','AB3:AB7'); zb = xlsread('test1.xlsx','Sheet1','AC3:AC7');

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