From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
---|---|
To: | Merlin Moncure <mmoncure(at)gmail(dot)com> |
Cc: | PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Subject: | Re: proposal: support empty string as separator for string_to_array |
Date: | 2009-07-27 16:42:06 |
Message-ID: | 162867790907270942y74dfc1acud8e9d22b5113c61e@mail.gmail.com |
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Lists: | pgsql-hackers |
2009/7/25 Merlin Moncure <mmoncure(at)gmail(dot)com>:
> On Fri, Jul 24, 2009 at 11:40 PM, Pavel Stehule<pavel(dot)stehule(at)gmail(dot)com> wrote:
>> Hello
>>
>> I have one idea, that should simplify string to char array
>> transformation. The base is idea: between every char is empty string,
>> so empty string is regular separator for string_to_array function.
>> This behave is inversion of array_to_string function behave:
>>
>> postgres=# select array_to_string(array['a','b','c'],'');
>> array_to_string
>> -----------------
>> abc
>> (1 row)
>>
>> postgres=# select string_to_array('abc','');
>> string_to_array
>> -----------------
>> {a,b,c}
>> (1 row)
>
> postgres=# select regexp_split_to_array('abc', '');
> regexp_split_to_array
> -----------------------
> {a,b,c}
> (1 row)
>
> :-)
>
I tested implementation and it's about 30% faster than using regexp.
I could to thing, 30% is significant reason for implementation.
regards
Pavel Stehule
> merlin
>
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