From 523bb1de834e9c05fec0f0d85330cfa15a3000b7 Mon Sep 17 00:00:00 2001
From: Tom Lane
Date: Wed, 30 Nov 2016 13:34:14 -0500
Subject: Doc: improve description of trim() and related functions.
Per bug #14441 from Mark Pether, the documentation could be misread,
mainly because some of the examples failed to show what happens with
a multicharacter "characters to trim" string. Also, while the text
description in most of these entries was fairly clear that the
"characters" argument is a set of characters not a substring to match,
some of them used variant wording that was a bit less clear.
trim() itself suffered from both deficiencies and was thus pretty
misinterpretable.
Also fix failure to explain which of LEADING/TRAILING/BOTH is the
default.
Discussion: https://postgr.es/m/20161130011710.6539.53657@wrigleys.postgresql.org
---
doc/src/sgml/func.sgml | 33 +++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)
(limited to 'doc/src')
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 79d25d84198..01e9489ddcf 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1306,11 +1306,12 @@
text
- Remove the longest string containing only the
+ Remove the longest string containing only characters from
characters (a space by default) from the
- start/end/both ends of the string
+ start, end, or both ends (both is the default)
+ of string
- trim(both 'x' from 'xTomxx')
+ trim(both 'xyz' from 'yxTomxx')
Tom
@@ -1319,14 +1320,14 @@
trim(leading | trailing
| both from
string
- , characters
+ , characters
)
text
- Non-standard version of trim()
+ Non-standard syntax for trim()
- trim(both from 'xTomxx', 'x')
+ trim(both from 'yxTomxx', 'xyz')
Tom
@@ -1398,7 +1399,7 @@
in characters (a space by default)
from the start and end of string
- btrim('xyxtrimyyx', 'xy')
+ btrim('xyxtrimyyx', 'xyz')
trim
@@ -1667,8 +1668,8 @@
characters (a space by default) from the start of
string
- ltrim('zzzytrim', 'xyz')
- trim
+ ltrim('zzzytest', 'xyz')
+ test
@@ -1950,8 +1951,8 @@
characters (a space by default) from the end of
string
- rtrim('trimxxxx', 'x')
- trim
+ rtrim('testxxzx', 'xyz')
+ test
@@ -3215,11 +3216,11 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
bytea
- Remove the longest string containing only the bytes in
+ Remove the longest string containing only bytes appearing in
bytes from the start
and end of string
- trim(E'\\000'::bytea from E'\\000Tom\\000'::bytea)
+ trim(E'\\000\\001'::bytea from E'\\000Tom\\001'::bytea)
Tom
@@ -3258,11 +3259,11 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
bytea
- Remove the longest string consisting only of bytes
- in bytes from the start and end of
+ Remove the longest string containing only bytes appearing in
+ bytes from the start and end of
string
- btrim(E'\\000trim\\000'::bytea, E'\\000'::bytea)
+ btrim(E'\\000trim\\001'::bytea, E'\\000\\001'::bytea)
trim
--
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