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PHP : Function Reference : String Functions : trim

trim

Strip whitespace (or other characters) from the beginning and end of a string (PHP 4, PHP 5)
string trim ( string str [, string charlist] )

Example 2480. Usage example of trim()

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<?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);

// trim the ASCII control characters at the beginning and end of $binary
// (from 0 to 31 inclusive)
$clean = trim($binary, "\x00..\x1F");
var_dump($clean);

?>

The above example will output:

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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(14) "Example string"

Example 2481. Trimming array values with trim()

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<?php
function trim_value(&$value)
{
   $value = trim($value);
}

$fruit = array('apple','banana ', ' cranberry ');
var_dump($fruit);

array_walk($fruit, 'trim_value');
var_dump($fruit);

?>

The above example will output:

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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"
}

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Examples ( Source code ) » Execute help command and check its output

Code Examples / Notes » trim

bishop
[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 = "&nbsp;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);
// &nbsp; are translated to 0xA0, so use:
$converted = trim($converted, "\xA0");
// PS: Thanks to John for saving my sanity!

thibs
[Editor's Note:
ltrim() is a better choice for this task. You can also use rtrim() to trim from the end of the string.
--zak@php.net]
To erase space just at the beginning of the string, use :
$string = eregi_replace("^[[:space:]]+", "", $string);

hw
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");

jonathan
With all this talk about trimming array values, it should be known that accidentally using the trim() function with an array() argument ...
<?php
 $array = array(1, 2, 3);
 $array = trim($array);
 print_r($array); // prints "Array"
 echo($array); // also prints "Array"
?>
... yields the string "Array"

tbm.at.home.dot.nl
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"
?>

martin kealey
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.

hayley
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().

webmaster __at__ digitalanime __dot__ nl
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);
?>
:)

cgi
To replace all excess white spaces with a single space try:
print $pizza = "One Two Three  Four";
$pizza = eregi_replace("[[:space:]]+", " ", $pizza);

jubi
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

abderzack host provider hotmail dot com
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.

13-oct-2000 10:25
To compact any number of spaces inside a string to a single space, use the following code:
print $pizza  = "Teil1           Teil2         Teil3     Teil4 Teil5 Teil6             df\n";
$pizza = ereg_replace (' +', ' ', $pizza);

asharm4
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.

hayley watson
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().

moehbass
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.

rwelti
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

rook
Recursive trim function for multi-dimensional arrays:
<?php
function trim_array($x)
{
   if (is_array($x)) {
       return array_map('trim_array', $x);
   }
   return trim($x);
}
$_POST = array_map('trim_array', $_POST);
?>

daggillies
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

dmr37
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!';
}
?>

lxg
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);
}
?>

davis_utah
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.

piopier
It may be useful to know that trim() returns an empty string when the argument is an unset/null variable.

04-mar-2005 06:25
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.

joshua dot logsdon
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.

removethisnospamkilling
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

asbo/at\iserv/dot\net
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');
?>

alivesay
If you are trying to take out whitespace from the middle of a string, you need to use a different function, str_replace:
<PRE>str_replace(" ", "", "United Kingdom);</PRE>
[Editor's note:
This strips *all* spaces present in the string, not just the ones in the middle
]

warhog
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 :-)

rchaube
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

24-jan-2007 04:04
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"

jayoungh5
I needed to trim whitespace on the left, on the right, in the middle, everywhere.  Here's a function to do it.  The first parameter ($hayStack) will have all the characters found in the second parameter ($whiteSpaceChars) removed from it.
function trimlrm ($hayStack, $whiteSpaceChars)
{
 $trimmmed = "";
 for ($i = 0; $i < strlen($hayStack); $i++)
 {
   if (strpos($whiteSpaceChars,$hayStack[$i]) === false)
     $trimmed .= $hayStack[$i];
 }
 return $trimmed;
}

olivierdsm
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

hkb
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;
}
?>

phazei
I had some issues using <? array_map('trim',$array) ?> when there was an array in array.  All arrays were replaced by the string "Array", drove me crazy.
Hopefully this will help someone:
<?
function trim_array($totrim) {
if (is_array($totrim)) {
$totrim = array_map("trim_array", $totrim);
} else {
$totrim = trim($totrim);
}
return $totrim;
}
?>
USE:
<?
$trimmed_array = trim_array($untrimmed_array);
?>
This function should recurse all embeded arrays.

ervin dot kosch
I find that when I use the explode() function to break apart string that read from a text file it sometime leave LF or CR that mess up my text processing.  So I wrote this function to get rid of any white spaces or CF/LF that might be causing a problem.
I have had some people report problems in older versions of PHP4.
<?
 function utrim($source){
   $temp = ltrim($source);
   $temp = rtrim($temp);
   $temp = trim($temp);

   return $temp;
 }
?>

thom
Hi everybody.
I make a registration page, and i want to drop \ t \n \r ...etc.
I send the trim function to the post but the trim not work good because if i send the post with \ t or \ r or \n it's work but later i have got an empty registration.
Here is the code:
$fullname = trim($_POST['regfullname']);
$messenger = trim($_POST['regmsn']);
$nick = trim($_POST['regnick']);
$telefon = trim($_POST['regtel']);
$email = trim($_POST['regemail']);
$www = trim($_POST['regwww']);
$pass1 = trim($_POST['regpassword1']);
$pass2 = trim($_POST['regpassword2']);
$icq = trim($_POST['regicq']);
$signature = trim($_POST['regsignature']);
$config = trim($_POST['regconfig']);
$protect = array(
"<" => "&lt;",
">" => "&gt;",
"&" => "&amp;",
"\"" => "&quot;",
"'" => "&#39;",
"\n" => " ",
"\t" => " ",
"\r" => " ",
"\0" => " ",
"\x0B" => "",
" " => ""
);
$protectmail = array(
"@" => "(KUKAC)",
"." => "(PONT)"
);
$fullname = strtr($fullname, $protect);
$messenger = strtr($messenger, $protect);
$nick = strtr($nick, $protect);
$telefon = strtr($telefon, $protect);
$email = strtr($email, $protectmail);
$www = strtr($www, $protect);
$pass1 = strtr($pass1, $protect);
$pass2 = strtr($pass2, $protect);
$icq = strtr($icq, $protect);
$signature = strtr($signature, $protect);
$config = strtr($config, $protect);

chris dot cowart
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 :)

15-jun-2005 05:54
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";
}

robin leffmann
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().

okumurya
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;
 }
?>

rifter
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.

j dot metzger
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

pinco pallino
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.

hayley watson
Another way to trim all the elements of an array
<?php
$newarray = array_map('trim', $array);
?>

admin
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;
}

manithu
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.

root
About trim all elements in an array.
May be
array_walk($db ,create_function('&$arr','$arr=trim($arr);'));
could be better than :
foreach ($db as $key=>$value) { $db[$key]=trim($value); }

mrizzo
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.

masteremployment
<?php
$string = 'This string      has        no       whitespaces.';
echo ereg_replace( '  +', '', $string ); //note: before '+' we have 2 spaces
?>
Output: This string has no white spaces.

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substr
trim
ucfirst
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