| From: | Andrew Dunstan <andrew(at)dunslane(dot)net> |
|---|---|
| To: | Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>, Michael Paquier <michael(at)paquier(dot)xyz> |
| Cc: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Gregory Smith <gregsmithpgsql(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, david(dot)christensen(at)crunchydata(dot)com |
| Subject: | Re: pgbench logging broken by time logic changes |
| Date: | 2021-06-24 12:03:27 |
| Message-ID: | c031d7e6-a903-bac0-be96-26adc8903e2c@dunslane.net |
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| Lists: | pgsql-hackers |
On 6/24/21 2:46 AM, Fabien COELHO wrote:
>
> Bonjour Michaël,
>
>> Using grep() with "$re" results in all the fields matching. Using on
>> the contrary "/$re/" in grep(), like list_files(), would only match
>> the first one, which is correct.
>
> Ok, good catch. Perl is kind of a strange language.
Not really, the explanation is fairly simple:
grep returns the values for which the test is true.
grep ("$re",@values) doesn't perform a regex test against the values, it
tests the truth of "$re" for each value, i.e. it's more or less the same
as grep (1, @values), which will always returns the whole @values list.
By contrast grep (/$re/, @values) returns those elements of @values that
match the regex.
cheers
andrew
--
Andrew Dunstan
EDB: https://www.enterprisedb.com
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