Add to CSV file

[Drew]

Is there anyway to directly insert rows into existing csv file - possibly similar to inserting into flat file?

[Ryan Hamilton]

Hi Drew,

Appending using a file handle works, I advise testing memory usage and
running on larger files.

// Write to file for first time
q)t:([] a:1 2 3; b:`pp`oo`ii)
q)save `t.csv
`:t.csv

// check contents
q)("**";",")0:`t.csv
,"a" ,"1" ,"2" ,"3"
,"b" "pp" "oo" "ii"

// append using file handle
q)h:hopen `:t.csv
q)neg[h] each ","0:value flip t
-164 -164 -164i

// check contents
q)("**";",")0:`t.csv
,"a" ,"1" ,"2" ,"3" ,"1" ,"2" ,"3"
,"b" "pp" "oo" "ii" "pp" "oo" "ii"

Regards,
Ryan Hamilton


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On 5/28/2013 11:29 AM, Drew wrote:
> Is there anyway to directly insert rows into existing csv file -

> possibly similar to inserting into flat file? --
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[Drew]

Ah excellent, cheers Ryan!

[Attila Vrabecz]

line-by-line is slow, do whole blocks instead
q)neg[h]","0:value flip t

Cheers,
   Attila

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