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Re: proposal: support empty string as separator for string_to_array

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 (view raw or flat)
Thread:
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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Subject: Re: proposal: support empty string as separator for string_to_array
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