Table values that is a scalar string

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Leon
Leon 2019-6-4
评论： Leon 2019-6-4
I use readtable to input an Excel file into Matlab.
T1 = readtable('AA.xlsx');
Now I know T1(3,48) = '32WC20110812', but I get an error when using the below command to assign the string to app.expo.Value:
app.expo.Value = T1(3,N);
Here is the error:
Error using matlab.ui.control.EditField/set.Value (line 98)
'Value' must be a character vector or a string scalar.
Error in A01_dataLoading_Tool/LoadheaderButtonPushed (line 279)
app.expo.Value = T1(3,N);
Error using matlab.ui.control.internal.controller.ComponentController/executeUserCallback (line 335)
Error while evaluating Button PrivateButtonPushedFcn.
What I'm missing? Thanks!

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Guillaume
Guillaume 2019-6-4
编辑：Guillaume 2019-6-4
As said in your previous question, read the doc about tables. For this particular case, the bits about table indexing.
() indexing on a table always return a table (just as () indexing on a cell array return a cell array even if it has just one cell).
To access the content of the table use {} indexing or . indexing:
T{3, N}
%or
T{3, 'variablename'} %where variablename is the name of the Nth variable
%or
T.variablename(3) %where variablename is the name of the Nth variable
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Guillaume
Guillaume 2019-6-4
If the Nth column of your table contains char vectors, it's possible that the underlying variable type is a cell array. In which case T{3, N} will be a single cell array and you need an additional {} indexing:
T{3, N}{1}
You can also use numeric indices for . indexing, in which case:
T.(N)(3)
which will also do the cell indexing for you.
Another way:
T.(T.Properties.VariableNames{N})(3) %but T.(N)(3) is simpler
Leon
Leon 2019-6-4
Thank you so much!
It seems that for strings it should be like the below though:
T.(N){3}
The problem is that sometimes it could be either a string or a number. In that case, what should I do, how can I predict which one to use {} or ()?

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per isakson
per isakson 2019-6-4
编辑：per isakson 2019-6-4
On my system Win10, R2018b, Excel 2016 all the methods to reference the last column works. (I downloaded AA.xlsx from another question.)
>> T1 = readtable( 'AA.xlsx')
Warning: Variable names were modified to make them valid MATLAB identifiers. The original
names are saved in the VariableDescriptions property.
T1 =
3×48 table
STNNBR CASTNO BTLNBR BTLNBR_FLAG_W DATE Year Month Day TIME LATITUDE LONGITUDE DEPTH CTDPRS CTDTMP CTDSAL CTDSAL_FLAG_W SALNTY SALNTY_FLAG_W CTDOXY CTDOXY_FLAG_W OXYGEN OXYGEN_FLAG_W SILCAT SILCAT_FLAG_W NITRAT NITRAT_FLAG_W NITRIT NITRIT_FLAG_W PHSPHT PHSPHT_FLAG_W AMMONI AMMONI_FLAG_W TCARBN TCARBN_FLAG_W ALKALI ALKALI_FLAG_W PH_TOT PH_TOT_FLAG_W PH_TMP CHLORA PON POC POC_PON PON_1 POC_1 LINE Accession EXPOCODE
______ ______ ______ _____________ __________ ____ _____ ___ _______ ________ _________ _____ ______ ______ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ _____________ ______ ______ ____ ____ _______ _____ _____ ____ __________ ______________
1 1 1 2 2011-08-12 2011 8 12 0.59839 47.11 -126.05 2292 2309.6 1.759 34.636 2 34.633 2 75.6 2 75.61 6 185.3 2 40.02 2 0.05 2 2.89 2 0.01 2 2386.8 6 2436.3 2 7.447 3 25 -999 -999 -999 -999 -999 -999 1 1.5746e+05 '32WC20110812'
1 1 2 2 2011-08-12 2011 8 12 0.5986 47.11 -126.05 2292 2309.6 1.759 34.636 2 -999 9 72 2 -999 9 -999 9 -999 9 -999 9 -999 9 -999 9 -999 9 -999 9 -999 9 -999 -999 0.37 3.75 10.2 0.38 3.86 1 1.5746e+05 '32WC20110812'
1 1 3 2 2011-08-12 2011 8 12 0.59976 47.11 -126.05 2292 2286.3 1.759 34.636 2 -999 9 71.9 2 -999 9 185.22 2 39.98 2 0.04 2 2.91 2 0.01 2 2385.8 2 2429.4 6 7.442 3 25 -999 -999 -999 -999 -999 -999 1 1.5746e+05 '32WC20110812'
>> T1.EXPOCODE
ans =
3×1 cell array
{'32WC20110812'}
{'32WC20110812'}
{'32WC20110812'}
>> T1{:,48}
ans =
3×1 cell array
{'32WC20110812'}
{'32WC20110812'}
{'32WC20110812'}
>> T1(:,48)
ans =
3×1 table
EXPOCODE
______________
'32WC20110812'
'32WC20110812'
'32WC20110812'
>>
>> T1(3,48)
ans =
table
EXPOCODE
______________
'32WC20110812'
>> T1.EXPOCODE(3)
ans =
1×1 cell array
{'32WC20110812'}
>> T1{3,48}
ans =
1×1 cell array
{'32WC20110812'}
>>
What value does app.expo.Value have before the assignment?

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