Thingspeakwrite error when using string array

This string of code is taken from the thingSpeak documentation for matlab. I just copy and paste but still got this error. I would very much appreciate it if anyone can tell me where i did wrong

[Geoff Hayes]

Dion - which version of MATLAB are you using? If you type doc thingSpeakWrite what does the documentation say about the data (second) input (are strings allowed)?

[Dion Guek]

My matlab version is 2017b student edition. Based on the attached picture above, the data can be a string. This is taken from the doumentation page from https://www.mathworks.com/help/thingspeak/thingspeakwrite.html

Answer 1

[Christopher Stapels]

When you write string data to ThingSpeak, it generally wants to have a cell array. You should not usually need to do the String() conversion yourself. Try

 thingSpeakWrite(349672,{ans},'Location',[-40,23],'WriteKey',writeKey);

and

 thingSpeakWrite(channelID,{2.3,'on','good'},'Location',[-40,23],'WriteKey',writeKey);

Ill have a look at fixing that documented example, thanks for pointing it out.

[Marc Hanssens]

what about with arrays? EG: dA,dB & dC are arrays of Doubles and sD is an array of strings

thingSpeakWrite(writeChannelID,'Fields',[1,2,3,4],'Values', [ dA, dB, dC, sD ], 'WriteKey', writeAPIKey, 'TimeStamp',tStamp);

[Christopher Stapels]

Generally, the field values cannot be arrays. You can write them as strings or cell arrays.

thingSpeakWrite(writeChannelID,'Fields',[1,2,3,4],'Values', [ {dA}, {dB}, {dC}, {sD} ], ...
    'WriteKey', writeAPIKey, 'TimeStamp',tStamp);