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Extract Column Headers from a CSV file?

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john

08 Feb, 2015 12:36 AM

I am visualizing CSV files. I can slice and dice the data but would also like to display and manipulate the column headers.

For some projects I need to do generic lookups without having to hand-code new key values every time I change a file. For example I'd like to simply display the contents of any CSV file - including the headers - as a full-fledged NodeBox visualization (with fonts, colors, grid spacing etc. under my full control) by simply changing the file in the Import Csv node.

All I need is some way to return the column header keys as individual strings. Even just a way of counting the number of columns in a CSV file would be helpful.

How do I do this in Nobebox 3?

Thanks in advance for any suggestions or comments!

John

1. Support Staff 1 Posted by lucasnijs on 10 Feb, 2015 07:41 PM

   

   In NB3 there is no direct way of getting this. I agree it should be possible. The only way at the moment is cheating by adding a row in your csv file: repeating the headers. Later on you have to omit these rows. I agree this is not a real solution. We'll look into this and see if this can not be handled in the next release.

   regards,

   Lucas

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2. Support Staff 2 Posted by john on 10 Feb, 2015 11:46 PM

   

   Thanks for the response, Lucas.

   If you are compiling a wish list I have another related feature request.

   It would be very handy to create a two dimensional zip map that would let me create and pass internal CSV data structures from node to node. As far as I can tell, the current zip map can only create a vector of label-value pairs, not a matrix with multiple index rows.

   The output of this improved zip map node would be a data structure just like the output of import CSV. Other nodes could then filter this output and do look ups on it. This would be a very powerful and useful capability.

   Doesn't hurt to ask.

   Thanks again,

   John

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3. Support Staff 3 Posted by lucasnijs on 11 Feb, 2015 03:40 PM

   

   Hello John,

   don't forget you can add your own code libraries. Enclosed is a file with a custom node that gets the headers as you want. Then you can count them too if you want...
   Have fun,

   Lucas
   PS: the csvheaders.py needs to be at the same root.

   • csvheaders.zip 1.83 KB
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4. Support Staff 4 Posted by john on 12 Feb, 2015 02:06 AM

   

   Nice! Thanks, Lucas.

   I was aware of the ability to add my own code libraries, but have been trying to resist it while I'm learning how to think in NodeBox. I find that staying within the standard nodes forces me to explore them more deeply. At first it often looks like something can't be done, but when you look a little deeper there is usually a way.

   But it's impressive how simple it was to add that custom node. Only six short lines of code. I'll keep this in mind next time I get stuck.

   Thanks again!

   John

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5. Support Staff 5 Posted by Stefan Gabriels on 12 Feb, 2015 06:43 AM

   

   In the next release there will be a getCSVHeaders node.

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6. Support Staff 6 Posted by Frederik De Ble... on 17 Feb, 2015 11:19 AM

   

   Hi,

   The new release, 3.0.43, contains the functionality you need. However, the node is called "keys", since it can retrieve the keys of any kind of map-related data, including CSV nodes.

   Another useful feature is that you can append it after a graphic object, in which case it will list the properties of that object that you can retrieve using the lookup node.

   https://www.nodebox.net/download/

   Best,

   F

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7. john closed this discussion on 25 Feb, 2015 07:56 AM.