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更多强大的字符串处理函数,参见 POSIX 正则表达式函数和 Perl 兼容正则表达式函数。
[#1] str at maphpia dot com [2013-07-03 20:19:24]
I was looking for a function to find the common substring in 2 different strings. I tried both the mb_string_intersect and string_intersect functions listed here but didn't work for me. I found the algorithm at http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Longest_common_substring#PHP so here I post you the function
<?php
function string_intersect($string_1, $string_2)
{
$string_1_length = strlen($string_1);
$string_2_length = strlen($string_2);
$return = "";
if ($string_1_length === 0 || $string_2_length === 0) {
// No similarities
return $return;
}
$longest_common_subsequence = array();
// Initialize the CSL array to assume there are no similarities
for ($i = 0; $i < $string_1_length; $i++) {
$longest_common_subsequence[$i] = array();
for ($j = 0; $j < $string_2_length; $j++) {
$longest_common_subsequence[$i][$j] = 0;
}
}
$largest_size = 0;
for ($i = 0; $i < $string_1_length; $i++) {
for ($j = 0; $j < $string_2_length; $j++) {
// Check every combination of characters
if ($string_1[$i] === $string_2[$j]) {
// These are the same in both strings
if ($i === 0 || $j === 0) {
// It's the first character, so it's clearly only 1 character long
$longest_common_subsequence[$i][$j] = 1;
} else {
// It's one character longer than the string from the previous character
$longest_common_subsequence[$i][$j] = $longest_common_subsequence[$i - 1][$j - 1] + 1;
}
if ($longest_common_subsequence[$i][$j] > $largest_size) {
// Remember this as the largest
$largest_size = $longest_common_subsequence[$i][$j];
// Wipe any previous results
$return = "";
// And then fall through to remember this new value
}
if ($longest_common_subsequence[$i][$j] === $largest_size) {
// Remember the largest string(s)
$return = substr($string_1, $i - $largest_size + 1, $largest_size);
}
}
// Else, $CSL should be set to 0, which it was already initialized to
}
}
// Return the list of matches
return $return;
}
[#2] Tomek Rychtyk [2012-02-08 21:58:00]
Get the intersection of two strings using array_intersect
<?php
function string_intersect($string1, $string2)
{
$array1 = $array2 = array();
for($i = 0, $j = 0, $s1_len = strlen($string1), $s2_len = strlen($string2);($i < $s1_len) || ($j < $s2_len); $i++, $j++) {
if($i < $s1_len) {
$array1[] = $string1[$i];
}
if($j < $s2_len) {
$array2[] = $string2[$j];
}
}
return implode('', array_intersect($array1, $array2));
}
?>
For more advanced comparison you can use array_uintersect as well.
[#3] Stephen Dewey [2008-11-19 17:33:07]
If you want a function to return all text in a string up to the Nth occurrence of a substring, try the below function.
Works in PHP >= 5.
(Pommef provided another sample function for this purpose below, but I believe it is incorrect.)
<?php
// Returns all of $haystack up to (but excluding) the $n_occurrence occurrence of $needle. Therefore:
// If there are < $n_occurrence occurrences of $needle in $haystack, the entire string will be returned.
// If there are >= $n_occurrence occurrences of $needle in $haystack, the returned string will end before the $n_occurrence'th needle.
// This function only makes sense for $n_occurrence >= 1
function nsubstr($needle, $haystack, $n_occurrence)
{
// After exploding by $needle, every entry in $arr except (possibly) part of the last entry should have its content returned.
$arr = explode($needle,$haystack,$n_occurrence);
// Examine last entry in $arr. If it contains $needle, cut out all text except for the text before $needle.
$last = count($arr) - 1;
$pos_in_last = strpos($arr[$last],$needle);
if ($pos_in_last !== false)
$arr[$last] = substr($arr[$last],0,$pos_in_last);
return implode($needle,$arr);
}
$string = 'd24jkdslgjldk2424jgklsjg24jskgldjk24';
print 'S: ' . $string . '<br>';
print '1: ' . nsubstr('24',$string,1) . '<br>';
print '2: ' . nsubstr('24',$string,2) . '<br>';
print '3: ' . nsubstr('24',$string,3) . '<br>';
print '4: ' . nsubstr('24',$string,4) . '<br>';
print '5: ' . nsubstr('24',$string,5) . '<br>';
print '6: ' . nsubstr('24',$string,6) . '<br>';
print '7: ' . nsubstr('24',$string,7) . '<br>';
?>
Note that this function can be combined with wordwrap() to accomplish a routine but fairly difficult web design goal, namely, limiting inline HTML text to a certain number of lines. wordwrap() can break your string using <br>, and then you can use this function to only return text up to the N'th <br>.
You will still have to make a conservative guess of the max number of characters per line with wordwrap(), but you can be more precise than if you were simply truncating a multiple-line string with substr().
See example:
<?php
$text = 'Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Pellentesque id massa. Duis sollicitudin ipsum vel diam. Aliquam pulvinar sagittis felis. Nullam hendrerit semper elit. Donec convallis mollis risus. Cras blandit mollis turpis. Vivamus facilisis, sapien at tincidunt accumsan, arcu dolor suscipit sem, tristique convallis ante ante id diam. Curabitur mollis, lacus vel gravida accumsan, enim quam condimentum est, vitae rutrum neque magna ac enim.';
$wrapped_text = wordwrap($text,100,'<br>',true);
$three_lines = nsubstr('<br>',$wrapped_text,3);
print '<br><br>' . $three_lines;
$four_lines = nsubstr('<br>',$wrapped_text,4);
print '<br><br>' . $four_lines;
?>
[#4] Verdauga [2008-03-19 18:06:52]
Just a note in regards to bloopletech a few posts down:
The word "and" should not be used when converting numbers to text. "And" (at least in US English) should only be used to indicate the decimal place.
Example:
1,796,706 => one million, seven hundred ninety-six thousand, seven hundred six.
594,359.34 => five hundred ninety four thousand, three hundred fifty nine and thirty four hundredths
[#5] m [2007-07-26 17:10:04]
Regarding the code for the function beginsWith($str, $sub), I found that it has problems when only one character is present after the string searched for. I found that this works better instead:
<?php
function beginsWith($str, $sub) {
return (strncmp($str, $sub, strlen($sub)) == 0);
}
?>
[#6] mike "eyes" moe [2007-06-17 17:59:43]
Here is a truly random string generator it uses the most common string functions it will work on anywhere.
<?php
function random_string($max = 20){
$chars = explode(" ", "a b c d e f g h i j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9");
for($i = 0; $i < $max; $i++){
$rnd = array_rand($chars);
$rtn .= base64_encode(md5($chars[$rnd]));
}
return substr(str_shuffle(strtolower($rtn)), 0, $max);
}
?>
[#7] admin at rotarymulundeast dot org [2006-07-30 03:16:42]
Here's an easier way to find nth...
function nth($numbex){
if ($numbex%10 == 1 && $numbex%100 != 11) $sth='st';
elseif ($numbex%10 == 2 && $numbex%100 != 12) $sth='nd';
elseif ($numbex%10 == 3 && $numbex%100 != 13) $sth='rd';
else $sth = 'th';
return $sth;
}
there is is no need to check if the user has entered a non-integer as we may be using this function for expressing variables as well eg. ith value of x , nth root of z ,etc...
[#8] da (dot) blayde (a t) gmail (dot) com [2006-07-19 10:52:49]
Sometimes when converting integers to strings, it looks better to have the number spelled out. I wrote this function that converts integers from -999 to 999 into spelled out strings:
function int2str($int=0){
$doOnes=true;
$neg=$int<0?true:false;
$int=abs(round($int));
$str='';
switch(strlen($int)){
case 1:$int='0'.$int;
case 2:$int='0'.$int;
case 3:$int.='';break;
default:return $int;
}
switch($int{0}){
case 1:$str.='one-hundred-';break;
case 2:$str.='two-hundred-';break;
case 3:$str.='three-hundred-';break;
case 4:$str.='four-hundred-';break;
case 5:$str.='five-hundred-';break;
case 6:$str.='six-hundred-';break;
case 7:$str.='seven-hundred-';break;
case 8:$str.='eight-hundred-';break;
case 9:$str.='nine-hundred-';break;
}
switch($int{1}){
case 1:
switch($int{2}){
case 0:$str.='ten-';break;
case 1:$str.='eleven-';break;
case 2:$str.='twelve-';break;
case 3:$str.='thirteen-';break;
case 4:$str.='fourteen-';break;
case 5:$str.='fifteen-';break;
case 6:$str.='sixteen-';break;
case 7:$str.='seventeen-';break;
case 8:$str.='eighteen-';break;
case 9:$str.='nineteen-';break;
}
$doOnes=false;
break;
case 2:$str.='twenty-';break;
case 3:$str.='thirty-';break;
case 4:$str.='forty-';break;
case 5:$str.='fifty-';break;
case 6:$str.='sixty-';break;
case 7:$str.='seventy-';break;
case 8:$str.='eighty-';break;
case 9:$str.='ninety-';break;
}
if($doOnes){
switch($int{2}){
case 1:$str.='one-';break;
case 2:$str.='two-';break;
case 3:$str.='three-';break;
case 4:$str.='four-';break;
case 5:$str.='five-';break;
case 6:$str.='six-';break;
case 7:$str.='seven-';break;
case 8:$str.='eight-';break;
case 9:$str.='nine-';break;
}}
$str=substr($str,0,-1);
if($neg){
$str='negative '.$str;
}
if($int=='000'){
$str='zero';
}
return $str;
}
Hope this helps someone,
-Blayde
[#9] administrador(ensaimada)sphoera(punt)com [2006-03-02 06:10:50]
I've prepared this simple function to obtain a string delimited between tags (not only XML tags!). Anybody needs something like this?.
<?php
function get_string_between($string, $start, $end){
$string = " ".$string;
$ini = strpos($string,$start);
if ($ini == 0) return "";
$ini += strlen($start);
$len = strpos($string,$end,$ini) - $ini;
return substr($string,$ini,$len);
}
$string = "this [custom] function is useless!!";
echo get_string_between($string,"[","]");
// must return "custom";
?>
more functions at http://www.sphoera.com
[#10] SteveRusin [2006-02-24 11:00:47]
The functions below:
function beginsWith( $str, $sub )
function endsWith( $str, $sub )
Are correct, but flawed. You'd need to use the === operator instead:
function beginsWith( $str, $sub ) {
return ( substr( $str, 0, strlen( $sub ) ) === $sub );
}
function endsWith( $str, $sub ) {
return ( substr( $str, strlen( $str ) - strlen( $sub ) ) === $sub );
}
Otherwise, endsWith would return "foobar.0" ends with ".0" as well as "0" or "00" or any amount of zeros because numerically .0 does equal 0.
[#11] navarr at gmail dot com [2005-12-20 18:24:48]
stripos for PHP4.x
<?php
function stripos($haystack,$needle) {
return strpos(strtoupper($haystack),strtoupper($needle));
}
?>
[#12] admin at fivestarbuy dot com [2005-10-21 09:18:13]
This example lets you parse an unparsed strings variables. Warning: This could cause security leaks if you allow users to pass $variables through this engine. I recommend only using this for your Content Management System.
<?php
$mytime=time();
$mydog="My Dog Ate My PHP!";
# Your Parsing String:
$s1 = 'Hyphen Variable Preserving: $mytime, and $mydog';
echo "Before: <br><br>$s1<br><br>";
# Remember, wherever you define this, it will not be defined GLOBAL into the function
# which is why we define it here. Defining it global could lead to security issues.
$vardata=get_defined_vars();
# Parse the string
$s1 = StrParse($s1,$vardata);
echo "After: <br><br>$s1";
function StrParse($str,$vardata) {
# Takes a string, or piece of data, that contains PHP Variables
# For example, unparsed variables like: Test using time: $mytime
# This example shows $mytime, and not the actual variable value.
# The end result shows the actual variable value of $mytime.
# This is useful for building a content management system,
# and directing your variables into your content data,
# where content is stored in a file or database, unparsed.
# Of course this could slow down page loads, but it's a good way
# to parse data from current variables into your loaded new data
# making it compatible.
# Then the variables are replaced with the actual variable..
$getvarkeys=array_keys($vardata);
$ret=$str;
for ($x=0; $x < count($getvarkeys); $x++) {
$myvar=$getvarkeys[$x];
#echo "Variable: " . $myvar . " [" . $vardata[$myvar] . "]<br>";
$ret=str_replace('$' . $myvar, $vardata[$myvar], $ret);
}
return $ret;
}
?>
[#13] [2005-10-17 15:27:35]
to: james dot d dot baker at gmail dot com
PHP has a builtin function for doing what your function does,
http://php.net/ucfirst
http://php.net/ucwords
[#14] webmaster at cafe-clope dot net [2005-08-13 16:40:18]
A comprehensive concatenation function, that works with array and strings
<?php
function str_cat() {
$args = func_get_args() ;
// Asserts that every array given as argument is $dim-size.
// Keys in arrays are stripped off.
// If no array is found, $dim stays unset.
foreach($args as $key => $arg) {
if(is_array($arg)) {
if(!isset($dim))
$dim = count($arg) ;
elseif($dim != count($arg))
return FALSE ;
$args[$key] = array_values($arg) ;
}
}
// Concatenation
if(isset($dim)) {
$result = array() ;
for($i=0;$i<$dim;$i++) {
$result[$i] = '' ;
foreach($args as $arg)
$result[$i] .= ( is_array($arg) ? $arg[$i] : $arg ) ;
}
return $result ;
} else {
return implode($args) ;
}
}
?>
A simple example :
<?php
str_cat(array(1,2,3), '-', array('foo' => 'foo', 'bar' => 'bar', 'noop' => 'noop')) ;
?>
will return :
Array (
[0] => 1-foo
[1] => 2-bar
[2] => 3-noop
)
More usefull :
<?php
$myget = $_GET ; // retrieving previous $_GET values
$myget['foo'] = 'b a r' ; // changing one value
$myget = str_cat(array_keys($myget), '=', array_map('rawurlencode', array_values($myget))) ;
$querystring = implode(ini_get('arg_separator.output'), $myget)) ;
?>
will return a valid querystring with some values changed.
Note that
<?php str_cat('foo', '&', 'bar') ; ?>
will return 'foo&bar', while
<?php str_cat(array('foo'), '&', 'bar') ; ?>
will return array(0 => foo&bar)
[#15] t0russ at gmail dot com [2005-06-14 10:38:26]
to kristin at greenaple dot on dot ca:
thanx for sharing.
your function in recursive form proved to be slightly faster and it returns false (as it should) when the character is not found instead of number 0:
<?php
function strnposr($haystack, $needle, $occurance, $pos = 0) {
return ($occurance<2)?strpos($haystack, $needle, $pos):strnposr($haystack,$needle,$occurance-1,strpos($haystack, $needle, $pos) + 1);
}
?>
[#16] rh at richardhoward dot net [2005-06-05 11:41:12]
<?php
//This sets SQL escaping to use slashes; for Sybase(/MSSQL)-style escaping
// ( ' --> '' ), set to true.
define('STR_SYBASE', false);
class Str {
function gpc2sql($gpc, $maxLength = false)
{
return Str::pure2sql(Str::gpc2pure($gpc), $maxLength);
}
function gpc2html($gpc, $maxLength = false)
{
return Str::pure2html(Str::gpc2pure($gpc), $maxLength);
}
function gpc2pure($gpc)
{
if (ini_get('magic_quotes_sybase'))
$pure = str_replace("''", "'", $gpc);
else $pure = get_magic_quotes_gpc() ? stripslashes($gpc) : $gpc;
return $pure;
}
function html2pure($html)
{
return html_entity_decode($html);
}
function html2sql($html, $maxLength = false)
{
return Str::pure2sql(Str::html2pure($html), $maxLength);
}
function pure2html($pure, $maxLength = false)
{
return $maxLength ? htmlentities(substr($pure, 0, $maxLength))
: htmlentities($pure);
}
function pure2sql($pure, $maxLength = false)
{
if ($maxLength) $pure = substr($pure, 0, $maxLength);
return (STR_SYBASE)
? str_replace("'", "''", $pure)
: addslashes($pure);
}
function sql2html($sql, $maxLength = false)
{
$pure = Str::sql2pure($sql);
if ($maxLength) $pure = substr($pure, 0, $maxLength);
return Str::pure2html($pure);
}
function sql2pure($sql)
{
return (STR_SYBASE)
? str_replace("''", "'", $sql)
: stripslashes($sql);
}
}
?>
[#17] james dot d dot baker at gmail dot com [2005-05-27 10:45:58]
<?php
function sentenceCase($s){
$str = strtolower($s);
$cap = true;
for($x = 0; $x < strlen($str); $x++){
$letter = substr($str, $x, 1);
if($letter == "." || $letter == "!" || $letter == "?"){
$cap = true;
}elseif($letter != " " && $cap == true){
$letter = strtoupper($letter);
$cap = false;
}
$ret .= $letter;
}
return $ret;
}
?>
[#18] php at moechofe dot com [2005-04-26 06:34:26]
<?php
function str_match( $str, $match )
{
$return = '';
if( eregi( '(.*)', $match, $class ) )
{
$match = '['.$regs[1].']';
for( $i=0; $i<strlen($str); $i++ )
if( ereg( '['.$class[1].']', $str[$i] ) )
$return .= $str{$i};
return $return;
}
else return false;
}
if( ! empty($_REQUEST['a']) )
$_REQUEST['a'] = str_match( $_REQUEST['a'], 'a-zA-Z0-9' );
else
$_REQUEST['a'] = 'default';
?>
[#19] Pommef [2005-03-19 13:15:56]
Example: Give me everything up to the fourth occurance of '/'.
<?php
$haystack = "/home/username/www/index.php";
$needle = "/";
function strnpos($haystack, $needle, $occurance, $pos = 0) {
$res = implode($needle,$haystack);
$res = array_slice($res, $pos, $occurance);
return explode ($needle,$res);
}
?>
[#20] kristin at greenapple dot on dot ca [2005-01-02 08:32:44]
I really searched for a function that would do this as I've seen it in other languages but I couldn't find it here. This is particularily useful when combined with substr() to take the first part of a string up to a certain point.
strnpos() - Find the nth position of needle in haystack.
<?php
function strnpos($haystack, $needle, $occurance, $pos = 0) {
for ($i = 1; $i <= $occurance; $i++) {
$pos = strpos($haystack, $needle, $pos) + 1;
}
return $pos - 1;
}
?>
Example: Give me everything up to the fourth occurance of '/'.
<?php
$haystack = "/home/username/www/index.php";
$needle = "/";
$root_dir = substr($haystack, 0, strnpos($haystack, $needle, 4));
echo $root_dir;
?>
Returns: /home/username/www
Use this example with the server variable $_SERVER['SCRIPT_NAME'] as the haystack and you can self-discover a document's root directory for the purposes of locating global files automatically!
[#21] [2004-12-20 20:31:47]
In response to hackajar <matt> yahoo <trot> com,
No string-to-array function exists because it is not needed. If you reference a string with an offset like you do with an array, the character at that offset will be return. This is documented in section III.11's "Strings" article under the "String access and modification by character" heading.
[#22] andy a t onesandzeros d o t biz [2004-11-09 14:54:25]
I use these little doo-dads quite a bit. I just thought I'd share them and maybe save someone a little time. No biggy. :)
// returns true if $str begins with $sub
function beginsWith( $str, $sub ) {
return ( substr( $str, 0, strlen( $sub ) ) == $sub );
}
// return tru if $str ends with $sub
function endsWith( $str, $sub ) {
return ( substr( $str, strlen( $str ) - strlen( $sub ) ) == $sub );
}
// trims off x chars from the front of a string
// or the matching string in $off is trimmed off
function trimOffFront( $off, $str ) {
if( is_numeric( $off ) )
return substr( $str, $off );
else
return substr( $str, strlen( $off ) );
}
// trims off x chars from the end of a string
// or the matching string in $off is trimmed off
function trimOffEnd( $off, $str ) {
if( is_numeric( $off ) )
return substr( $str, 0, strlen( $str ) - $off );
else
return substr( $str, 0, strlen( $str ) - strlen( $off ) );
}
[#23] [tab!] [2004-10-27 12:29:09]
//
// string strtrmvistl( string str, [int maxlen = 64],
// [bool right_justify = false],
// [string delimter = "<br>\n"])
//
// splits a long string into two chunks (a start and an end chunk)
// of a given maximum length and seperates them by a given delimeter.
// a second chunk can be right-justified within maxlen.
// may be used to 'spread' a string over two lines.
//
function strtrmvistl($str, $maxlen = 64, $right_justify = false, $delimter = "<br>\n") {
if(($len = strlen($str = chop($str))) > ($maxlen = max($maxlen, 12))) {
$newstr = substr($str, 0, $maxlen - 3);
if($len > ($maxlen - 3)) {
$endlen = min(($len - strlen($newstr)), $maxlen - 3);
$newstr .= "..." . $delimter;
if($right_justify)
$newstr .= str_pad('', $maxlen - $endlen - 3, ' ');
$newstr .= "..." . substr($str, $len - $endlen);
}
return($newstr);
}
return($str);
}
[#24] terry dot greenlaw at logicalshift dot com [2004-08-11 22:52:56]
Here's a simpler "simplest" way to toggle through a set of 1..n colors for web backgrounds:
<?php
$colours = array('#000000', '#808080', '#A0A0A0', '#FFFFFF');
// Get a colour
$color = next($colors) or $color = reset($colors);
?>
The code doesn't need to know anything about the number of elements being cycled through. That way you won't have to tracking down all the code when changing the number of colors or the color values.