Query large CSV file as a data source?

[matthias_livecode_150811 at m-r-d.de]

Couldn't you read the file partially

you would open the file for read

	open file tFile for read

then in a repeat loop you could read e.g. 10000 lines and process the data

	read from file tFile for 10000 lines


Just a thought.


-
Matthias Rebbe
Life Is Too Short For Boring Code

> Am 03.11.2020 um 13:14 schrieb Keith Clarke via use-livecode <use-livecode at lists.runrev.com>:
> 
> Hi folks,
> I’ve a 3GB CSV file with 18M rows from which I need to create a subset CSV file for the rows containing tString. The following script results in LiveCode becoming unresponsive, so I’m wondering if I’m missing an obvious trick or what alternative approach I might take...
> on mouseUp pButtonNumber
> 
> -- Select CSV File
> 
> answer file prompt as sheet
> 
> put it into tFile
> 
> put tFile into field "File"
> 
> -- Process CSV extract
> 
> put URL ("file:" & tFile) into tText
> 
> put line 1 of tText into field "List"
> 
> filter lines of tText with "*tString*"
> 
> put tText into field tList
> 
> end mouseUp
> 
> I don’t normally deal with large data sets, so maybe LiveCode isn’t the best tool for this but Excel 365 seems to only offer CSV file import, not query.
> 
> Any thoughts greatly appreciated.
> 
> Thanks & regards,
> Keith
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