How can I export a matrix as a CSV file?
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Toby Feld
le 26 Avr 2016
Commenté : Chris
le 2 Nov 2022
Hi,
I have a 320x2 matrix with doubles. I want to save it in a CSV file in the following pattern:
234,2 671,5 735,1 264,2 346,7 ... etc.
I googled this problem and found the function "csvwrite". However, when I use that function like this
csvwrite('test.txt',a)
I get the following:
234,2671,5735,1264,2346,7
What is going on here? How can I solve this issue?
Thanks a lot, Toby
2 commentaires
jgg
le 26 Avr 2016
Why do you want to export it like that? It seems really unnatural, and will be annoying to accomplish.
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MathWorks Support Team
le 27 Fév 2020
When writing matrix data to a file, you can specify the file type as part of the file name in the second argument of the function call:
m = [234 2;671 5;735 1;264 2;346 7]
writematrix(m,'M.csv')
4 commentaires
Chris
le 2 Nov 2022
Look at your file hierarchy on the left you'll see a file that's been generated with the name you gave it. You can right click and show it in explorer.
Plus de réponses (4)
Azzi Abdelmalek
le 26 Avr 2016
a=[234,2
671,5
735,1]
csvwrite('file.csv',a)
4 commentaires
Bill Tubbs
le 13 Juil 2019
Being a Python user coming to Matlab I was a bit shocked to find that csvwrite truncates the data output.
csvwrite('u.csv', u)
File contents:
1000,957.6,917,878.13,840.9, ...
Then I happened to check the documentation and found this:
csvwrite is not recommended. Use writematrix instead. For more information, see Compatibility Considerations.
writematrix(u)
File contents:
1000,957.603280698574,917.004043204671,878.12608018665,840.896415253715, ...
Guillaume
le 13 Juil 2019
writematrix is fairly new and did not exist when this question was ask.
I was a bit shocked to find that csvwrite truncates the data output.
Any conversion of number to text will truncate the representation of most numbers, in python as well. As documented csvwrite has a precision of 5 digits. For more precision, the alternative at the time was dlmwrite. Interestingly writematrix also doesn't have an option of altering the precision and always use longg (15 digits of precision).
Jos (10584)
le 26 Avr 2016
You and your computer disagree on what to use as a decimal symbol: a . or a ,
I strongly recommend you to use a decimal point. Probably that means you have to change your locale / regional settings in the operating system.
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Sindar
le 12 Mar 2019
It sounds like all you need to do is print a column vector instead of a row vector. This can be done easily:
csvwrite('test.txt',a.')
The '.' is important only if you have complex data
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