trim
(PHP 4, PHP 5)
trim — Удаляет пробелы (или другие символы) из начала и конца строки
Описание
Эта функция возвращает строку str с удаленными из начала и конца строки пробелами. Если второй параметр не передан, trim() удаляет следующие символы:
- " " (ASCII 32 (0x20)), обычный пробел.
- "\t" (ASCII 9 (0x09)), символ табуляции.
- "\n" (ASCII 10 (0x0A)), символ перевода строки.
- "\r" (ASCII 13 (0x0D)), символ возврата каретки.
- "\0" (ASCII 0 (0x00)), NUL-байт.
- "\x0B" (ASCII 11 (0x0B)), вертикальная табуляция.
Список параметров
- str
-
Обрезаемая строка (string).
- charlist
-
Можно также задать список символов для удаления с помощью необязательного аргумента charlist. Просто перечислите все символы, которые вы хотите удалить. Можно указать конструкцию .. для обозначения диапазона символов.
Возвращаемые значения
Обрезаемая строка.
Список изменений
| Версия | Описание |
|---|---|
| 4.1.0 | Добавлен необязательный параметр charlist. |
Примеры
Пример #1 Пример использования trim()
<?php
$text = "\t\tThese are a few words :) ... ";
$binary = "\x09Example string\x0A";
$hello = "Hello World";
var_dump($text, $binary, $hello);
print "\n";
$trimmed = trim($text);
var_dump($trimmed);
$trimmed = trim($text, " \t.");
var_dump($trimmed);
$trimmed = trim($hello, "Hdle");
var_dump($trimmed);
$trimmed = trim($hello, 'HdWr');
var_dump($trimmed);
// удаляем управляющие ASCII-символы с начала и конца $binary
// (от 0 до 31 включительно)
$clean = trim($binary, "\x00..\x1F");
var_dump($clean);
?>
Результат выполнения данного примера:
string(32) " These are a few words :) ... " string(16) " Example string " string(11) "Hello World" string(28) "These are a few words :) ..." string(24) "These are a few words :)" string(5) "o Wor" string(9) "ello Worl" string(14) "Example string"
Пример #2 Обрезание значений массива с помощью trim()
<?php
function trim_value(&$value)
{
$value = trim($value);
}
$fruit = array('apple','banana ', ' cranberry ');
var_dump($fruit);
array_walk($fruit, 'trim_value');
var_dump($fruit);
?>
Результат выполнения данного примера:
array(3) {
[0]=>
string(5) "apple"
[1]=>
string(7) "banana "
[2]=>
string(11) " cranberry "
}
array(3) {
[0]=>
string(5) "apple"
[1]=>
string(6) "banana"
[2]=>
string(9) "cranberry"
}
Примечания
Замечание: Возможные трюки: удаление символов из середины строки
Так как trim() удаляет символы с начала и конца строки string, то удаление (или неудаление) символов из середины строки может ввести в недоумение. trim('abc', 'bad') удалит как 'a', так и 'b', потому что удаление 'a' сдвинет 'b' к началу строки, что также позволит ее удалить. Вот почему это "работает", тогда как trim('abc', 'b') очевидно нет.
Смотрите также
- ltrim() - Удаляет пробелы (или другие символы) из начала строки
- rtrim() - Удаляет пробелы (или другие символы) из конца строки
- str_replace() - Заменяет все вхождения строки поиска на строку замены
- addcslashes
- addslashes
- bin2hex
- chop
- chr
- chunk_split
- convert_cyr_string
- convert_uudecode
- convert_uuencode
- count_chars
- crc32
- crypt
- echo
- explode
- fprintf
- get_html_translation_table
- hebrev
- hebrevc
- hex2bin
- html_entity_decode
- htmlentities
- htmlspecialchars_decode
- htmlspecialchars
- implode
- join
- lcfirst
- levenshtein
- localeconv
- ltrim
- md5_file
- md5
- metaphone
- money_format
- nl_langinfo
- nl2br
- number_format
- ord
- parse_str
- printf
- quoted_printable_decode
- quoted_printable_encode
- quotemeta
- rtrim
- setlocale
- sha1_file
- sha1
- similar_text
- soundex
- sprintf
- sscanf
- str_getcsv
- str_ireplace
- str_pad
- str_repeat
- str_replace
- str_rot13
- str_shuffle
- str_split
- str_word_count
- strcasecmp
- strchr
- strcmp
- strcoll
- strcspn
- strip_tags
- stripcslashes
- stripos
- stripslashes
- stristr
- strlen
- strnatcasecmp
- strnatcmp
- strncasecmp
- strncmp
- strpbrk
- strpos
- strrchr
- strrev
- strripos
- strrpos
- strspn
- strstr
- strtok
- strtolower
- strtoupper
- strtr
- substr_compare
- substr_count
- substr_replace
- substr
- trim
- ucfirst
- ucwords
- vfprintf
- vprintf
- vsprintf
- wordwrap
Коментарии
Windows uses two characters for definining newlines, namely ASCII 13 (carriage return, "\r") and ASCII 10 (line feed, "\n") aka CRLF. So if you have a string with CRLF's, trim() won't recognize them as being one newline. To solve this you can use str_replace() to replace the CRLF's with with a space or something.
<?php
// string with bunch of CRLF's
$my_string = "Liquid\r\nTension Experiment\r\n\r\n\r\n";
// replace CRLF's with spaces
$my_wonderful_string = str_replace("\r\n", " ", $my_string);
// would result in "Liquid Tension Experiment "
// or just delete the CRLF's (by replacing them with nothing)
$my_wonderful_string = str_replace("\r\n", "", $my_string);
// would result in "LiquidTension Experiment"
?>
If you want to totally stop windows (dunno about other os's) peeps from adding spaces (say, you need to check there name against a special one to stop impersonations) use this:
$nick = ereg_replace("[\r\n\t\v\ ]", "", trim($nick));
It has the alt code 0160 added to it
Be careful when you use the charlist with the hex-codes...
use e.g. \x22 instead of \0x22 (this last thing won't work).
An example to strip quotes ' " ' (double quotes) and " ' " (single quotes) is to do this:
$example[0]='"hello"';
$example[1]="'baby'"
foreach ($example as $key => $val)
$example[$key]=trim($val,"\x22\x27");
# this works brilliant, but be aware:
# $example[$key]=trim($val,"\0x22\0x27");
# won't work !!!
-> tested on php 4.2.1
NOTE:
All the above examples using ereg_replace with an escape code of \v are BROKEN! \v is NOT an escape code in PHP. Using a regexp of \v e.g.
$str=ereg_replace("[\r\t\n\v]","",$str);
will remove any instances of the letter 'v' from your string. So 'Activity' becomes 'Actiity'. Probably not what you want.
Here is a small function I use to strip whitespace from the end of strings and squash repeated whitespace down to a single space in the middle of strings:
function wsstrip(&$str)
{
$str=ereg_replace (' +', ' ', trim($str));
$str=ereg_replace("[\r\t\n]","",$str);
}
David Gillies
San Jose
Costa Rica
In response to the line mentioned above...
$clean = trim($binary,"\0x00..\0x1F");
I was also able to get
$clean = trim($binary,"\0x00-\0x1F");
to function.
[Editor: I botched my last note; please delete and use this one]
Non-breaking spaces can be troublesome with trim (as per an earlier comment):
// turn some HTML with non-breaking spaces into a "normal" string
$myHTML = " abc";
$converted = strtr($myHTML, array_flip(get_html_translation_table(HTML_ENTITIES, ENT_QUOTES)));
// this WILL NOT work as expected
// $converted will still appear as " abc" in view source
// (but not in od -x)
$converted = trim($converted);
// are translated to 0xA0, so use:
$converted = trim($converted, "\xA0");
// PS: Thanks to John for saving my sanity!
I just wanted to say that when you want to do a LDAP query based on a form value (i mean something like : <form method="POST" action="script_createnewticket.php" name="demande2">) dynamicaly updated from a popup javascript , (for example <a onclick=" opener.document.forms['demande2'].elements['thename3'].value='my name') it doesn't work.
It took me 2 days to find out that when you use trim, to "convert" the value, then it works.
-------------------------
$thename4=trim($thename3);
$ds=ldap_connect("$myldapserver"); // connects to the LDAP SERVER
if (!($ds = ldap_connect("$myldapserver") ) ) {
die ("Could not connect to LDAP server");
}
$r=ldap_bind($ds, "cn=".$NTusername, $NTpassword);
$sr = ldap_search($ds, ' ', "uid=".$thename4);
$info = ldap_get_entries($ds, $sr);
-------------------------------------
only on this case you will get results.
Strange and good to know
You can combine character ranges and individual characters in trim()'s second argument (ditto for ltrim and rtrim). All of the specified characters and ranges will be used concurrently (i.e., if a character on either end of the string matches any of the specified charaters or character ranges, it will be trimmed). The characters and character ranges can be in any order (except of course that the character ranges need to be specified in increasing order) and may overlap.E.g., trim any nongraphical non-ASCII character:
trim($text,"\x7f..\xff\x0..\x1f");
Regarding the editor's note to rhelic above about how to trim all elements in an array:
I wanted a perl "chomp" of newlines for all elements in an array.
I tried array_filter for a long time, but rhelic's straightforward way is what worked.
// chomp newlines off all elements in stations array
$stations = array_filter($stations, 'trim'); // editor's way - nope
foreach ($stations as $key => $value) {
$stations[$key] = trim($value); } // works fine
using PHP 4.3.1 on Solaris
About trim all elements in an array.
array_filter($db, 'trim') doesn't work becouse it does NOT modify array's elements, it only returns a copy from those elements which return true on the callback function.
I think that:
foreach ($db as $key=>$value) { $db[$key]=trim($value); }
still being the best option.
To remove multiple occurences of whitespace characters in a string an convert them all into single spaces, use this:
<?
$text = preg_replace('/\s+/', ' ', $text);
?>
------------
JUBI
http://www.jubi.buum.pl
To:
mrizzo at advancedsl dot com dot ar
And what about array_map()? :)
<?php
$myarray = array(
'hello' => ' bye ',
'hey' => ' howdie',
'haai' => ' today'
);
array_map('trim', $myarray);
?>
:)
To eliminate all the empty strings from my array, I used the array_filter, that way :
1.
I defined a function returning true iff the passed as parameter string is NOT empty.
function notEmpty($string)
{
return !empty($string);
}
2.Use array filter :
$myarray = array_filter($myarray ,"notEmpty");
That's it.
Of course, if you want to prove your mama you can write unreadable code, you can create an anonymous function, by using the create_function, instead of declaring the function notEmpty.
Hope that will help you.
Another way to trim all the elements of an array<?php
$newarray = array_map('trim', $array);
?>
It is important to stress that trim() only removes whitespace characters from the *beginning* and *end* of str. To remove whitespace characters embedded within a string (newlines, for instance) you can use str_replace(), searching for and destroying both \n and \r characters.An faster (and eleganter) way than using regular expressions to check if a string only contains whitespaces is to use trim().
Example:
<?php
if (!trim($foobar)) {
echo 'The string $foobar is empty!';
}
?>
I hope this helps somebody.
Another recursive trim function for multi-dimensional arrays ( uses only trim function :)
function array_trim($arr, $charlist=null){
foreach($arr as $key => $value){
if (is_array($value)) $result[$key] = array_trim($value, $charlist);
else $result[$key] = trim($value, $charlist);
}
return $result;
}
Note that manithu's post on 29-Mar-2005 02:49 for identifying strings that only contain whitespaces will also identify strings like "0" and " 0 " as being empty. If you want to check whether something ONLY has whitespaces, use the following:
<?php
if (trim($foobar)=='') {
echo 'The string $foobar only contains whitespace!';
}
?>
fread/fwrite blocks program when no data available.
so, you consider use select system call.
following is example.
<?php
/**
*
* write/read pipe
*
* @param resource $w_fp write file handle
* @param resource $r_fp read file handle
* @param string $input
* @return string
*/
function _writeread_pipe(&$w_fp, &$r_fp, $input) {
$output = '';
$write_bytes = 0;
//
while (True) {
if (!isset($r_fp) && !isset($w_fp)) break;
$read = isset($r_fp) ? array($r_fp) : Null;
$write = isset($w_fp) ? array($w_fp) : Null;
// select pipes
$r = stream_select($read,
$write,
$except = Null,
30
);
if ($r === False) {
return PEAR::raiseError('process timeout');
}
// read pipe
if (isset($read) && isset($read[0])) {
do {
$buf = fread($r_fp, 1024);
if (strlen($buf) == 0) {
fclose($r_fp);
$r_fp = Null;
break;
}
$output .= $buf;
} while (True);
}
// write pipe
if (isset($write) && isset($write[0])) {
$r = fwrite($w_fp, substr($input, $write_bytes));
if ($r === False) {
return PEAR::raiseError('process write error');
}
$write_bytes += $r;
if ($write_bytes == strlen($input)) {
fclose($w_fp);
$w_fp = Null;
}
}
}
return $output;
}
?>
here's a heads up folks.
in the event that you want to check the result of a trim for being empty the following code fails::
$emptyvar = " ";
if ( empty(trim($emptyvar)) )
{
echo "It was empty";
}
this code works as expected::
$emptyvar = " ";
$check = trim($emptyvar);
if ( empty($check) )
{
echo "It was empty";
}
Here's a neat function to trim off extraneous zeros and the decimal, leaving important numbers intact:
<?php
function clean_num($num){
return trim(trim($num, '0'), '.');
}
echo clean_num('06000.3050');
echo clean_num('500.00');
?>
Output:
6000.305
500
I find it very handy to use when pulling data from decimal fields in MySQL and putting them into <input> fields. Makes everything cleaner :)
Chris wrote:
> Here's a neat function to trim off extraneous zeros and the > decimal, leaving important numbers intact:
> ...
Actually use:
<?php
...
return rtrim(trim($num, '0'), '.');
...
?>
This ensures that a left leading decimal place doesn't get removed i.e. 00.010 should return .01 and not 01.
Just a word of caution when looping through a batch of strings (in the thousands or more). Using trim to take off a left over character (like a comma in a csv output) will result in a much slower execution. It is better to use a tiny bit of conditional logic instead.
I believe the reason this is the case is because of having to create a new spot in memory to temporarily handle the result of trim.
Hope this helps.
I was wondering about much of the examples given below, but the current (2005-12-07) function definition in the manual is not correct.
The function trim is defined as
trim(string string [, string charlist])
you must give the string-parameter and you can optionally add a parameter charlist - these chars are the chars to strip from the beginning and the end of the file.
(its self-evident that the default of this parameter is "\n\t\r\h\v\0 ")
hope that'll help - and that the docs are updated.. i don't know since which php-version that optional parameter can be used - i know that it works with PHP >= 4.3 & >= 5.0 . Maybe it's beeing there since 10 years and just an enormous insider :-)
Using "trim" to minimize the format of a decimal number strikes me as awkward. I would just use:
$str += 0;
This even has the added benefit of ensuring that you have at least one digit (and thus have a valid number) even if the original was empty.
This staetment removes the trailing and leading whitespaces from the string..Really useful when handling the form values submitted by a visitor or analyzing a log file.
$trimmed_string = preg_replace ( "/\s\s+/" , " " , $untrimmed_string );
Note : thsi would only remove leading and trailing whitespaces. For the whitespaces in the string use any of the above methods.
I was accepting text pasted from a csv file into a textarea in my code. I found that even using trim was not able to get rid of the whitespace characters at the end of the string.
Finally, using this helped:
$result = trim($source,"\x7f..\xff\x0..\x1f");
Hope this saves someone few hours. All thanks to previous comment from HW for this
I had some issues using <? array_map('trim',$array) ?> when there was an array in array. All arrays were replaced by the string "Array", drove me crazy.
Hopefully this will help someone:
<?php
function trim_array($totrim) {
if (is_array($totrim)) {
$totrim = array_map("trim_array", $totrim);
} else {
$totrim = trim($totrim);
}
return $totrim;
}
?>
USE:
<?php
$trimmed_array = trim_array($untrimmed_array);
?>
This function should recurse all embeded arrays.
If you need to trim a string from the beginning and end of a string, then this function maybe prove handy.
<?php
function lrclean($str,$rm) {
$i = strlen($rm);
do {
if (substr($str,0,$i) == $rm) {$str = substr($str,$i);}
} while (substr($str,0,$i) == $rm);
do {
if (substr($str,-$i,$i) == $rm) {$str = substr($str,0,-$i);}
} while (substr($str,-$i,$i) == $rm);
return $str;
}
// prints 'text'
echo lrclean('xyztextxyz','xyz');
?>
It may be useful to know that trim() returns an empty string when the argument is an unset/null variable.I use this to remove leading, trailing and "more than one" space in between words.
$pat[0] = "/^\s+/";
$pat[1] = "/\s{2,}/";
$pat[2] = "/\s+\$/";
$rep[0] = "";
$rep[1] = " ";
$rep[2] = "";
$str = " Words with lots of spaces ";
$str = preg_replace($pat,$rep,$str);
// Output
"Words with lots of spaces"
trim's code can of course be simplified with some use of the trim() function....
<?php
$str = " Words with lots of spaces ";
$str = preg_replace('/\s\s+/', ' ', trim($str));
?>
Doing the trim() first reduces the workload being put on the more expensive preg_replace().
Here's a faster way to do what's described below:
<?php
$string = 'This string has no whitespaces.';
echo ereg_replace( ' +', '', $string );
?>
Output: Thisstringhasnowhitespaces.
If you want it to replace only single whitespaces instead of both single and cascading dito, remove the + in the first parameter of ereg_replace().
Responding to Robin Leffmann:jayoungh5 wrote a function to trim whitespace on the left, on the right, in the middle, everywhere (Below). It iterates through the string's characters. Yours, claimed to be faster, uses a regex function. I think it should be slower since I believe that dealing with a regex is iterative in nature and add to that the possibility of recursion! Perhaps your function is shorter in code lines.
I am not absolutely positive, so take this as a clue but research for a more solid truth.
Robin Leffman's code could be improved further...
<?php
$string = 'This string has no whitespaces.';
echo str_replace(' ', '', $string );
?>
Of course, like Leffman's code, that only removes space characters, not necessarily all whitespace (or characters in some arbitrary $whiteSpace string). For that
<?php
function trimlrm ($hayStack, $whiteSpaceChars)
{
$char = $whiteSpaceChars[0];
$chars = str_repeat($char, strlen($whiteSpaceChars);
$trimmed = strtr($hayStack, $whiteSpaceChars, $chars)));
return str_replace($char, '', $trimmed);
}
?>
would probably work, but like the others, fails to give '..' the same specialness that it has in trim().
masteremployment's solution in a function, and with preg_replace() instead of ereg_replace():
<?php
function removeWhitespace($string)
{
if (!is_string($string))
return false;
$string = preg_quote($string, '|');
return preg_replace('| +|', ' ', $string);
}
?>
I have made this simple function to trim the whole string instead of just the beginning and end...
<?php
function strTrimTotal($input) {
$input = trim($input);
for($i=0;$i<strlen($input);$i++) {
if(substr($input, $i, 1) != " ") {
$output .= trim(substr($input, $i, 1));
} else {
$output .= " ";
}
}
return $output;
}
?>
As already commented by thers the solution from Robin Leffmann to remove "all"
the spaces from a string not only does not trim the "other" chars besides plain
spaces but is at all not faster than jayoungh5's proposal.
The only faster way I can imagine of is:
function trimall($str, $charlist = " \t\n\r\0\x0B")
{
return str_replace(str_split($charlist), '', $str);
}
However jayoungh5's one might still be faster for very large sets of characters
to be stripped.
as mentioned, a str_replace(' ', '', $string) does execute faster than Robin Leffmann's ereg_replace; however, the regular expression Leffmann supplied has the ability of also stripping out only -single- whitespaces as by his comment, whereas the blunt str_replace will simply sweep all of them away, single as cascading. one tool for each job.admin at semaster dot ru's array_trim function is flawed in that it will change the type of nulls and numeric variables (to strings).
Here is a better version, although it lacks charlist support:
<?php
function array_trim($var) {
if (is_array($var))
return array_map("array_trim", $var);
if (is_string($var))
return trim($var);
return $var;
}
?>
-Rob
I've noticed that many needs to remove multiple lines in the end of a string, so I made this function. Pretty easy, actually. It removes all unnecessary newlines (or something else, if $char is set)
<?php
function remove_unnecessary ($str, $char = "\n") {
while (true) {
if (substr ($str, -(strlen($char))) == $char) {
$str = substr ($str, 0, -(strlen($char)));
} else {
break;
}
}
return $str;
}
$Str = "Hello\nHello\n\n\n\n\n\n\n\n\n";
// Outputs: Hello\nHello
echo remove_unnecessary ($Str);
?>
Yet another array trim, recursive too.
I think this one is pretty usefull, though it lacks charlist, you can add that functionality if you need to, it's not that hard ;)
Anyway, one feature that I added, and I find pretty usefull, is that it can splice an empty position if you want to
<?php
function array_trim_recursive(&$array, $splice_empty = true) {
foreach($array as $k => &$v) {
if(is_array($v)) {
array_trim_recursive($v, $splice_empty);
} else {
$array[$k] = trim($v);
iif(!$v && $splice_empty) {
array_splice($array, $k, 1);
}
}
}
}
?>
If you want to remove all excessive spaces and leave just a single one, like the way HTML text gets rendered in the browser, this function (modified from one posted here earlier) will work:
function str_squeeze($test) {
return trim(ereg_replace( ' +', ' ', $test));
}
The result is that a string such as "hello___how_are__you_" (where the _ is a space) will result in a more sane "hello_how_are_you".
The following function will assist you in case you wish to trim a string but keep the parts trimmed. I'm using it to strip phrases for translation on my site.
Example:
cleanPhrase(' (this () is it)');
Will return:
Array
(
[left] => (
[right] => )
[clean] => this () is it
)
<?php
/**
* Trims some of the characters from the phrase
*
* @param string $phrase - to be "cleaned"
* @param string $dirtyChars - the characters that need be removed
* @return string
*/
public static function cleanPhrase($phrase, $dirtyChars = " \t\n()[]:.\"'") {
$len = strlen($phrase);
for($i=0; $i < $len; $i++) {
$pos = strpos($dirtyChars, substr($phrase, $i, 1));
if ($pos === false) break;
}
for($j=$len-1; $j >= 0; $j--) {
$pos = strpos($dirtyChars, substr($phrase, $j, 1));
if ($pos === false) break;
}
$res = array();
$res['left'] = substr($phrase, 0, $i);
$res['right'] = substr($phrase, $j+1);
$res['clean'] = substr($phrase, $i, $j-$i+1);
return $res;
}
?>
A simple function to clear extra white spaces along a string.
<?php
function TrimStr($str)
{
$str = trim($str);
for($i=0;$i < strlen($str);$i++)
{
if(substr($str, $i, 1) != " ")
{
$ret_str .= trim(substr($str, $i, 1));
}
else
{
while(substr($str,$i,1) == " ")
{
$i++;
}
$ret_str.= " ";
$i--; // ***
}
}
return $ret_str;
}
?>
[EDIT BY danbrown AT php DOT net: Contains a fix provided by (info AT deep-soft DOT com) to address the issue where "it deletes the first char after spaces (because of while)."]
some of "trim array" functionsthis trim strings, arrays and objects:
<?php
function trimA($str, $set=null)
{
if(is_Array($str) || is_Object($str))
foreach($str as &$s)
$s=trimA($s,$set);
elseif($set===null)$str=trim($str);
else $str=trim($str,$set);
return $str;
}
?>
If what you need is delete a string instead of character, this function could help you:
<?php
function trimString($input, $string){
$input = trim($input);
$startPattern = "/^($string)+/i";
$endPattern = "/($string)+$/i";
return trim(preg_replace($endPattern, '', preg_replace($startPattern,'',$input)));
}
?>
Use:
<?php
echo trimString(" Hello world!. I said hello", "hello")
?>
Will return:
world!. I said
small fix for the trimString function to proof against slash and backslash:
<?php
function trimString($input, $string){
$input = trim($input);
$string = str_replace("\\", "\\\\", $string);
$string = str_replace('/', '\\/', $string);
$startPattern = "/^($string)+/i";
$endPattern = "/($string)+$/i";
return trim(preg_replace($endPattern, '', preg_replace($startPattern,'',$input)));
}
?>
I made this function to trim texts.
Removes al double horizontal and vertical whitespace chars.
<?php
function trimText($str)
{
$str = trim($str);
$str = preg_replace('/\h+/', ' ', $str);
$str = preg_replace('/\v{3,}/', PHP_EOL.PHP_EOL, $str);
return $str;
}
?>
A cell read from an Excel sheet appeared to have a whitespace, and this was not getting trimmed. By converting to hex, it seems the char was a hard return.
Successfully trimmed it by:
<?php
trim($value, "\xc2\xa0");
?>
The actual hex values may vary by character set, check with bin2hex() for what's actually there.
It should be mentioned that if you use the second charlist parameter, you are overriding the defaults, not adding to them. You would need to either explicitly add them to the charlist or call trim twice, like so:
<?php
$str = trim(trim($str), './@#$');
?>
Note for trimming arrays that you can easily use array_map if you don't want to specify the characters.
<?php
var_dump(array_map('trim', Array(' Test ', 'Test ', ' Test')));
?>
As another poster has pointed out, chr(160) is also important to filter out. This is the ascii representation of an html "hard space", and it will show up sometimes in your datasources, especially if the data was copied-and-pasted from a web browser from a page that used hard spaces to force layout.
This is not just a Windows problem. I am on a Mac and I have had to deal with it too (although the data in question may have indeed originally come from a windows user, I don't know.)
Admendum to this note:
<?php
// trim the ASCII control characters at the beginning and end of $binary
// (from 0 to 31 inclusive)
$clean = trim($binary, "\x00..\x1F");
?>
I had a big time with my WWW parser, which produced XML errors because of illegal characters in the outside files. So I decided to wipe them out.
If you want to remove all illegal SGML characters (ASCII coces 0 to 31 inclusive and 127 to 159 inclusive) from the whole string, (remember that trim doesn't work inside a string, just on the borders) here's how to do that:
<?php
$title = "Autobus zamiast \x1EHetmana\x1D ";
$replaceArray = array(array(), array()); // this is a replace array for illegal SGML characters;
for ($i=0; $i<32; $i++) // produces a correct XML output
{
$replaceArray[0][] = chr($i);
$replaceArray[1][] = "";
}
for ($i=127; $i<160; $i++)
{
$replaceArray[0][] = chr($i);
$replaceArray[1][] = "";
}
$title = str_replace($replaceArray[0], $replaceArray[1], $title); // get rid of illegal SGML chars
echo $title; // prints out "Autobus zamiast Hetmana"
?>
Now $title can be printed into an XML/XHTML file without worries.
There is a trap when making "form prefilters". Something like$_POST = array_map('trim', $_POST)
may be not what we wanted, because when there are arrays in form made by field[] this "prefilter" return not an array but, according to his behavior, string. So as a effect we see in var_dump not array but field = "Array" what can mess up our validation.
Trims occurances of every word in an array from the beginning and end of a string + whitespace and optionally extra single characters as per normal trim()
<?php
function trim_words($what, $words, $char_list = '') {
if(!is_array($words)) return false;
$char_list .= " \t\n\r\0\x0B"; // default trim chars
$pattern = "(".implode("|", array_map('preg_quote', $words)).")\b";
$str = trim(preg_replace('~'.$pattern.'$~i', '', preg_replace('~^'.$pattern.'~i', '', trim($what, $char_list))), $char_list);
return $str;
}
// for example:
$trim_list = array('AND', 'OR');
$what = ' OR x = 1 AND b = 2 AND ';
print_r(trim_words($what, $trim_list)); // => "x = 1 AND b = 2"
$what = ' ORDER BY x DESC, b ASC, ';
print_r(trim_words($what, $trim_list, ',')); // => "ORDER BY x DESC, b ASC"
?>
While inserting data from web forms to databases, trimming the posted values to remove the spaces from the left and right sides can be a good idea to avoid the user faults. This code have to be located before the DB operations.
<?php
/* Stripping whitespaces from left and right sides of all posted data.
* Put this before working with posted data.
*
*/
// Remove whitespaces from left and right sides.
function removeSpaces($str) {
$newStr = trim($str);
return $newStr;
}
// If any data posted to the page, send them for trimming.
if ($_POST) {
foreach ($_POST as $var => $value) {
$value=removeSpaces($value);
$_POST[$var] = $value;
}
}
?>
Non-breaking spaces can be troublesome with trim:
<?php
// turn some HTML with non-breaking spaces into a "normal" string
$myHTML = " abc";
$converted = strtr($myHTML, array_flip(get_html_translation_table(HTML_ENTITIES, ENT_QUOTES)));
// this WILL NOT work as expected
// $converted will still appear as " abc" in view source
// (but not in od -x)
$converted = trim($converted);
// are translated to 0xA0, so use:
$converted = trim($converted, "\xA0"); // <- THIS DOES NOT WORK
// EDITED>>
// UTF encodes it as chr(0xC2).chr(0xA0)
$converted = trim($converted,chr(0xC2).chr(0xA0)); // should work
// PS: Thanks to John for saving my sanity!
?>
Please consider the following:
<?php
$a = '0';
if (trim($a)) {
echo 'Never ever ...';
} else {
echo 'YES, "(bool)trim(\'0\')" is FALSE';
}
?>
So never forget to use:
if (trim($a) != '') ...
This cast costs me some time...
To trim all strings and remove CR.
<?php
$arr = array('apple', 'orange');
$arr2 = array('name' => 'James', 'zipcode' => '1234', $arr);
$data = array($arr2, 'peach');
array_walk_recursive($data, 'trim_all');
print_r($data);
function trim_all(&$value)
{
if (is_array($value))
{
array_walk_recursive($value, 'trim_all');
}
else
{
$value = trim(str_replace("\r\n", "\n", $value));
}
}
?>
Here's a function to trim strings recursively within an array.
<?php
// Trim a string or an array of strings recursively
function trim_r($array) {
if (is_string($array)) {
return trim($array);
} else if (!is_array($array)) {
return '';
}
$keys = array_keys($array);
for ($i=0; $i<count($keys); $i++) {
$key = $keys[$i];
if ( is_array($array[$key]) ) {
$array[$key] = trim_r($array[$key]);
} else if ( is_string($array[$key]) ) {
$array[$key] = trim($array[$key]);
}
}
return $array;
}
// Test
$a = array(' cat ', ' dog ' => ' mouse ', 234);
print_r(trim_r($a));
?>
Array
(
[0] => cat
[ dog ] => mouse
[1] => 234
)
On my application I had several users submit what to me appeared as "empty strings", whereas in fact they were submitting the ­ character.
Trim, by default, does not strip this character (Though arguably it should). The following code strips this character from your input:
<?php
// As the ­ character is invisible we'll simply use the ASCII numeric representation, and decode via chr():
$string = trim($string, chr(173));
// If you wish to strip all occurences this will work:
$string = str_replace(chr(173), "", $string);
?>
Gerard
Combined filter and trim array.
<?php
function _trim_value(&$value) {
if (is_string($value))
$value = trim($value);
}
function array_filter_and_trim($arr) {
array_walk($arr, '_trim_value');
return array_filter($arr);
}
?>
trim_chars
(trim string or character off beginning and end of a string)
<?php
function trim_chars($string,$char,$whitespace_first=null){
$string = ($whitespace_first ? trim($string) : $string);
$trimmed = ( substr($string,-1)==$char ? substr($string,($string[0]==$char ? 1 : 0),-1) : substr($string,($string[0]==$char ? 1 : 0)) );
return ( $trimmed == $string ? $trimmed : trim_str($trimmed,$char) );
}
?>
usage:
<?php
echo trim_chars('&%$abc&%$', '&%$');
echo trim_chars(' &%$abc&%$ ', '&%$', true);
echo trim_chars(' %%%abc%%% ', '&%$', false);
echo trim_chars('&%$abc&%$ ', '&%$', false);
?>
outputs:
'abc'
'abc'
' &%$abc&%$ '
'abc&%$ '
If you want to trim html whitespace ( entities and <br /> tags) you can use this function. Input should be valid utf8.
<?php
function htmltrim($string)
{
$pattern = '(?:[ \t\n\r\x0B\x00\x{A0}\x{AD}\x{2000}-\x{200F}\x{201F}\x{202F}\x{3000}\x{FEFF}]| |<br\s*\/?>)+';
return preg_replace('/^' . $pattern . '|' . $pattern . '$/u', '', $string);
}
?>
Here is a way to eliminate all the intermediate whitespaces in a string, but leaving just one whitespace in order to keep data such as names in a correct order.
example:
<?php
$text = "john doe doe";
//here is the function
while(substr_count($text," ") != 0){
$text = str_replace(" "," ",$text);
}
//The result would be: john doe doe
?>
Alternate way to trim and combine duplicate whitespace characters in a string:<?php
$text = " john q. doe ";
$text = trim(implode(' ', preg_split('/\s+/', $text)));
?>
I needed a quick function to check if a string was "trimmable".
Maybe some of you could need this:
function trim_check($str){
if(strlen($str) > strlen(trim($str))) return true;
else return false;
}