Regular expression that splits CSV string into table

On Fri, Sep 10, 2010 at 3:43 PM, Nick <nboutelier@gmail.com> wrote:

What would be the regexp_split_to_table pattern that splits a comma
separated string into a table? Im having trouble when a string
contains commas or there are commas at the beginning or end

String
',one,two,''three,four'',five,six,'

Should return
,one
two
three,four
five
six,

You can roll your own function, or try regexp_split_to_table, though
you will probably have to use a different delimiter if you don't want
it to break on "three,four".
Eg.

select regexp_split_to_table('"one","two","three,four","five"',',');
regexp_split_to_table
-----------------------
"one"
"two"
"three
four"
"five"

Yes, that gets down to the root of my question... what is the
expression that would properly split the values? -Nick

Excerpts from Nick's message of vie sep 10 20:36:24 -0400 2010:

Yes, that gets down to the root of my question... what is the
expression that would properly split the values? -Nick

The only idea that comes to mind right now is to remove them before
processing the rest of the string, and put them back to the first and
last element if they were removed.

--
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
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I dont mind if the commas are at the beginning and end, im more
concerned about "three,four" staying in one row because its surrounded
by quotes. -Nick

On Fri, 2010-09-10 at 18:11 -0700, Nick wrote:

I dont mind if the commas are at the beginning and end, im more
concerned about "three,four" staying in one row because its surrounded
by quotes. -Nick

It doesn't sound like a regex is the best solution here. Why not write a
function in a language that offers a CSV library, like python?

Regards,
Jeff Davis