Related
This is my sample string (this one has five words; in practice, there may be more):
$str = "I want to filter it";
Output that I want:
$output[1] = array("I","want","to","filter","it");
$output[2] = array("I want","want to","to filter","filter it");
$output[3] = array("I want to","want to filter","to filter it");
$output[4] = array("I want to filter","want to filter it");
$output[5] = array("I want to filter it");
What I am trying:
$text = trim($str);
$text_exp = explode(' ',$str);
$len = count($text_exp);
$output[$len][] = $text; // last element
$output[1] = $text_exp; // first element
This gives me the first and the last arrays. How can I get all the middle arrays?
more generic solution that works with any length word:
$output = array();
$terms = explode(' ',$str);
for ($i = 1; $i <= count($terms); $i++ )
{
$round_output = array();
for ($j = 0; $j <= count($terms) - $i; $j++)
{
$round_output[] = implode(" ", array_slice($terms, $j, $i));
}
$output[] = $round_output;
}
You can do that easily with regular expressions that give you the most flexibility. See below for the way that supports dynamic string length and multiple white characters between words and also does only one loop which should make it more efficient for long strings..
<?php
$str = "I want to filter it";
$count = count(preg_split("/\s+/", $str));
$results = [];
for($i = 1; $i <= $count; ++$i) {
$expr = '/(?=((^|\s+)(' . implode('\s+', array_fill(0, $i, '[^\s]+')) . ')($|\s+)))/';
preg_match_all($expr, $str, $matches);
$results[$i] = $matches[3];
}
print_r($results);
You can use a single for loop and if conditions to do
$str = "I want to filter it";
$text = trim($str);
$text_exp = explode(' ',$str);
$len = count($text_exp);
$output1=$text_exp;
$output2=array();
$output3=array();
$output4=array();
$output5=array();
for($i=0;$i<count($text_exp);$i++)
{
if($i+1<count($text_exp) && $text_exp[$i+1]!='')
{
$output2[]=$text_exp[$i].' '.$text_exp[$i+1];
}
if($i+2<count($text_exp) && $text_exp[$i+2]!='')
{
$output3[]=$text_exp[$i].' '.$text_exp[$i+1].' '.$text_exp[$i+2];
}
if($i+3<count($text_exp) && $text_exp[$i+3]!='')
{
$output4[]=$text_exp[$i].' '.$text_exp[$i+1].' '.$text_exp[$i+2].' '.$text_exp[$i+3];
}
if($i+4<count($text_exp) && $text_exp[$i+4]!='')
{
$output5[]=$text_exp[$i].' '.$text_exp[$i+1].' '.$text_exp[$i+2].' '.$text_exp[$i+3].' '.$text_exp[$i+4];
}
}
I have a string abcxdefxghix. I wish to remove all "x"s except the first one. I can easily find the position of the first "x" using strpos(), so wish to remove all "x"s after that position. str_replace() performs a replacement of a given string with another, but doesn't allow a start position. substr_replace() gives a start position, but doesn't have the search parameter. I realize this can be done using preg_replace() but it seems like it should also be possible with without regular expressions (or without some crazy split/replace/assemble strategy).
You could do something like this:
list($first,$remainder) = explode($searchString,$subjectString,2);
$remainder = str_replace($searchString,$replacementString,$remainder);
$resultString = $first.$searchString.$remainder;
I 'd most likely do it the old-fashioned way:
$index = strpos($input, $needle);
if ($index !== false) {
$input = substr($input, 0, $index + 1).
str_replace($needle, $replacement, substr($input, $index + 1));
}
I thought there had to be an easier way, but evidently there isn't. My homespun function was negligently faster, but if there is an "old-fashion way", it is probably the way to go.
function replace_all_but_first_1($search,$replace,$subject){
$pos=strpos($subject,$search);
return ($pos===false)?$subject:substr($subject,0,$pos+1).str_replace($search,$replace,substr($subject, $pos));
}
function replace_all_but_first_2($search,$replace,$subject){
$index = strpos($subject, $search);
if ($index !== false) {
$subject = substr($subject, 0, $index + 1).
str_replace($search, $replace, substr($subject, $index + 1));
}
return $subject;
}
function replace_all_but_first_3($search,$replace,$subject){
list($first,$remainder) = explode($search,$subject,2);
$remainder = str_replace($search,$replace,$remainder);
$resultString = $first.$search.$remainder;
return $resultString;
}
function replace_all_but_first($search,$replace,$subject){
echo('Replace "'.$search.'" with "'.$replace.'" in "'.$subject.'"<br><br>');
echo('replace_all_but_first_1: '.replace_all_but_first_1($search,$replace,$subject)."<br>");
echo('replace_all_but_first_2: '.replace_all_but_first_2($search,$replace,$subject)."<br>");
echo('replace_all_but_first_3: '.replace_all_but_first_3($search,$replace,$subject)."<br>");
$time=microtime(true);
for ($i = 1; $i <= 100000; $i++) {$x=replace_all_but_first_1($search,$replace,$subject);}
echo('replace_all_but_first_1 '.(microtime(true)-$time).'<br>');
$time=microtime(true);
for ($i = 1; $i <= 100000; $i++) {$x=replace_all_but_first_2($search,$replace,$subject);}
echo('replace_all_but_first_2 '.(microtime(true)-$time).'<br>');
$time=microtime(true);
for ($i = 1; $i <= 100000; $i++) {$x=replace_all_but_first_3($search,$replace,$subject);}
echo('replace_all_but_first_3 '.(microtime(true)-$time).'<br>');
echo('<br><br><br>');
}
replace_all_but_first('x','','abcxdefxghix');
replace_all_but_first('x','','xabcxdefxghix');
replace_all_but_first('z','','abcxdefxghix');
Replace "x" with "" in "abcxdefxghix"
replace_all_but_first_1: abcxdefghi
replace_all_but_first_2: abcxdefghi
replace_all_but_first_3: abcxdefghi
replace_all_but_first_1 0.18973803520203
replace_all_but_first_2 0.19031405448914
replace_all_but_first_3 0.19151902198792
Replace "x" with "" in "xabcxdefxghix"
replace_all_but_first_1: xabcdefghi
replace_all_but_first_2: xabcdefghi
replace_all_but_first_3: xabcdefghi
replace_all_but_first_1 0.18725895881653
replace_all_but_first_2 0.19358086585999
replace_all_but_first_3 0.19228482246399
Replace "z" with "" in "abcxdefxghix"
replace_all_but_first_1: abcxdefxghix
replace_all_but_first_2: abcxdefxghix
replace_all_but_first_3: abcxdefxghixz
replace_all_but_first_1 0.074465036392212
replace_all_but_first_2 0.075581073760986
replace_all_but_first_3 0.71253705024719
I have a string that that is an unknown length and characters.
I'd like to be able to truncate the string after x amount of characters.
For example from:
$string = "Hello# m#y name # is Ala#n Colem#n"
$character = "#"
$x = 4
I'd like to return:
"Hello# m#y name # is Ala#"
Hope I'm not over complicating things here!
Many thanks
I'd suggest explode-ing the string on #, then getting the 1st 4 elements in that array.
$string = "Hello# m#y name # is Ala#n Colem#n";
$character = "#";
$x = 4;
$split = explode($character, $string);
$split = array_slice($split, 0, $x);
$newString = implode($character, $split).'#';
function posncut( $input, $delim, $x ) {
$p = 0;
for( $i = 0; $i < $x; ++ $i ) {
$p = strpos( $input, $delim, $p );
if( $p === false ) {
return "";
}
++ $p;
}
return substr( $input, 0, $p );
}
echo posncut( $string, $character, $x );
It finds each delimiter in turn (strpos) and stops after the one you're looking for. If it runs out of text first (strpos returns false), it gives an empty string.
Update: here's a benchmark I made which compares this method against explode: http://codepad.org/rxTt79PC. Seems that explode (when used with array_pop instead of array_slice) is faster.
Something along these lines:
$str_length = strlen($string)
$character = "#"
$target_count = 4
$count = 0;
for ($i = 0 ; $i<$str_length ; $i++){
if ($string[$i] == $character) {
$count++
if($count == $target_count) break;
}
}
$result = sub_str($string,0,$i)
I have a small search engine doing its thing, and want to highlight the results. I thought I had it all worked out till a set of keywords I used today blew it out of the water.
The issue is that preg_replace() is looping through the replacements, and later replacements are replacing the text I inserted into previous ones. Confused? Here is my pseudo function:
public function highlightKeywords ($data, $keywords = array()) {
$find = array();
$replace = array();
$begin = "<span class=\"keywordHighlight\">";
$end = "</span>";
foreach ($keywords as $kw) {
$find[] = '/' . str_replace("/", "\/", $kw) . '/iu';
$replace[] = $begin . "\$0" . $end;
}
return preg_replace($find, $replace, $data);
}
OK, so it works when searching for "fred" and "dagg" but sadly, when searching for "class" and "lass" and "as" it strikes a real issue when highlighting "Joseph's Class Group"
Joseph's <span class="keywordHighlight">Cl</span><span <span c<span <span class="keywordHighlight">cl</span>ass="keywordHighlight">lass</span>="keywordHighlight">c<span <span class="keywordHighlight">cl</span>ass="keywordHighlight">lass</span></span>="keywordHighlight">ass</span> Group
How would I get the latter replacements to only work on the non-HTML components, but to also allow the tagging of the whole match? e.g. if I was searching for "cla" and "lass" I would want "class" to be highlighted in full as both the search terms are in it, even though they overlap, and the highlighting that was applied to the first match has "class" in it, but that shouldn't be highlighted.
Sigh.
I would rather use a PHP solution than a jQuery (or any client-side) one.
Note: I have tried to sort the keywords by length, doing the long ones first, but that means the cross-over searches do not highlight, meaning with "cla" and "lass" only part of the word "class" would highlight, and it still murdered the replacement tags :(
EDIT: I have messed about, starting with pencil & paper, and wild ramblings, and come up with some very unglamorous code to solve this issue. It's not great, so suggestions to trim/speed this up would still be greatly appreciated :)
public function highlightKeywords ($data, $keywords = array()) {
$find = array();
$replace = array();
$begin = "<span class=\"keywordHighlight\">";
$end = "</span>";
$hits = array();
foreach ($keywords as $kw) {
$offset = 0;
while (($pos = stripos($data, $kw, $offset)) !== false) {
$hits[] = array($pos, $pos + strlen($kw));
$offset = $pos + 1;
}
}
if ($hits) {
usort($hits, function($a, $b) {
if ($a[0] == $b[0]) {
return 0;
}
return ($a[0] < $b[0]) ? -1 : 1;
});
$thisthat = array(0 => $begin, 1 => $end);
for ($i = 0; $i < count($hits); $i++) {
foreach ($thisthat as $key => $val) {
$pos = $hits[$i][$key];
$data = substr($data, 0, $pos) . $val . substr($data, $pos);
for ($j = 0; $j < count($hits); $j++) {
if ($hits[$j][0] >= $pos) {
$hits[$j][0] += strlen($val);
}
if ($hits[$j][1] >= $pos) {
$hits[$j][1] += strlen($val);
}
}
}
}
}
return $data;
}
I've used the following to address this problem:
<?php
$protected_matches = array();
function protect(&$matches) {
global $protected_matches;
return "\0" . array_push($protected_matches, $matches[0]) . "\0";
}
function restore(&$matches) {
global $protected_matches;
return '<span class="keywordHighlight">' .
$protected_matches[$matches[1] - 1] . '</span>';
}
preg_replace_callback('/\x0(\d+)\x0/', 'restore',
preg_replace_callback($patterns, 'protect', $target_string));
The first preg_replace_callback pulls out all matches and replaces them with nul-byte-wrapped placeholders; the second pass replaces them with the span tags.
Edit: Forgot to mention that $patterns was sorted by string length, longest to shortest.
Edit; another solution
<?php
function highlightKeywords($data, $keywords = array(),
$prefix = '<span class="hilite">', $suffix = '</span>') {
$datacopy = strtolower($data);
$keywords = array_map('strtolower', $keywords);
$start = array();
$end = array();
foreach ($keywords as $keyword) {
$offset = 0;
$length = strlen($keyword);
while (($pos = strpos($datacopy, $keyword, $offset)) !== false) {
$start[] = $pos;
$end[] = $offset = $pos + $length;
}
}
if (!count($start)) return $data;
sort($start);
sort($end);
// Merge and sort start/end using negative values to identify endpoints
$zipper = array();
$i = 0;
$n = count($end);
while ($i < $n)
$zipper[] = count($start) && $start[0] <= $end[$i]
? array_shift($start)
: -$end[$i++];
// EXAMPLE:
// [ 9, 10, -14, -14, 81, 82, 86, -86, -86, -90, 99, -103 ]
// take 9, discard 10, take -14, take -14, create pair,
// take 81, discard 82, discard 86, take -86, take -86, take -90, create pair
// take 99, take -103, create pair
// result: [9,14], [81,90], [99,103]
// Generate non-overlapping start/end pairs
$a = array_shift($zipper);
$z = $x = null;
while ($x = array_shift($zipper)) {
if ($x < 0)
$z = $x;
else if ($z) {
$spans[] = array($a, -$z);
$a = $x;
$z = null;
}
}
$spans[] = array($a, -$z);
// Insert the prefix/suffix in the start/end locations
$n = count($spans);
while ($n--)
$data = substr($data, 0, $spans[$n][0])
. $prefix
. substr($data, $spans[$n][0], $spans[$n][1] - $spans[$n][0])
. $suffix
. substr($data, $spans[$n][1]);
return $data;
}
I had to revisit this subject myself today and wrote a better version of the above. I'll include it here. It's the same idea only easier to read and should perform better since it uses arrays instead of concatenation.
<?php
function highlight_range_sort($a, $b) {
$A = abs($a);
$B = abs($b);
if ($A == $B)
return $a < $b ? 1 : 0;
else
return $A < $B ? -1 : 1;
}
function highlightKeywords($data, $keywords = array(),
$prefix = '<span class="highlight">', $suffix = '</span>') {
$datacopy = strtolower($data);
$keywords = array_map('strtolower', $keywords);
// this will contain offset ranges to be highlighted
// positive offset indicates start
// negative offset indicates end
$ranges = array();
// find start/end offsets for each keyword
foreach ($keywords as $keyword) {
$offset = 0;
$length = strlen($keyword);
while (($pos = strpos($datacopy, $keyword, $offset)) !== false) {
$ranges[] = $pos;
$ranges[] = -($offset = $pos + $length);
}
}
if (!count($ranges))
return $data;
// sort offsets by abs(), positive
usort($ranges, 'highlight_range_sort');
// combine overlapping ranges by keeping lesser
// positive and negative numbers
$i = 0;
while ($i < count($ranges) - 1) {
if ($ranges[$i] < 0) {
if ($ranges[$i + 1] < 0)
array_splice($ranges, $i, 1);
else
$i++;
} else if ($ranges[$i + 1] < 0)
$i++;
else
array_splice($ranges, $i + 1, 1);
}
// create substrings
$ranges[] = strlen($data);
$substrings = array(substr($data, 0, $ranges[0]));
for ($i = 0, $n = count($ranges) - 1; $i < $n; $i += 2) {
// prefix + highlighted_text + suffix + regular_text
$substrings[] = $prefix;
$substrings[] = substr($data, $ranges[$i], -$ranges[$i + 1] - $ranges[$i]);
$substrings[] = $suffix;
$substrings[] = substr($data, -$ranges[$i + 1], $ranges[$i + 2] + $ranges[$i + 1]);
}
// join and return substrings
return implode('', $substrings);
}
// Example usage:
echo highlightKeywords("This is a test.\n", array("is"), '(', ')');
echo highlightKeywords("Classes are as hard as they say.\n", array("as", "class"), '(', ')');
// Output:
// Th(is) (is) a test.
// (Class)es are (as) hard (as) they say.
OP - something that's not clear in the question is whether $data can contain HTML from the get-go. Can you clarify this?
If $data can contain HTML itself, you are getting into the realms attempting to parse a non-regular language with a regular language parser, and that's not going to work out well.
In such a case, I would suggest loading the $data HTML into a PHP DOMDocument, getting hold of all of the textNodes and running one of the other perfectly good answers on the contents of each text block in turn.
Firstly, I want to inform that, what I need is the reverse of in_array PHP function.
I need to search all items of array in the string if any of them found, function will return true otherwise return false.
I need the fastest solution to this problem, off course this can be succeeded by iterating the array and using the strpos function.
Any suggestions are welcome.
Example Data:
$string = 'Alice goes to school every day';
$searchWords = array('basket','school','tree');
returns true
$string = 'Alice goes to school every day';
$searchWords = array('basket','cat','tree');
returns false
You should try with a preg_match:
if (preg_match('/' . implode('|', $searchWords) . '/', $string)) return true;
After some comments here a properly escaped solution:
function contains($string, Array $search, $caseInsensitive = false) {
$exp = '/'
. implode('|', array_map('preg_quote', $search))
. ($caseInsensitive ? '/i' : '/');
return preg_match($exp, $string) ? true : false;
}
function searchWords($string,$words)
{
foreach($words as $word)
{
if(stristr($string," " . $word . " ")) //spaces either side to force a word
{
return true;
}
}
return false;
}
Usage:
$string = 'Alice goes to school every day';
$searchWords = array('basket','cat','tree');
if(searchWords($string,$searchWords))
{
//matches
}
Also take note that the function stristr is used to make it not case-sensitive
As per the example of malko, but with properly escaping the values.
function contains( $string, array $search ) {
return 0 !== preg_match(
'/' . implode( '|', preg_quote( $search, '/' ) ) . '/',
$string
);
}
If string can be exploded using space following will work:
var_dump(array_intersect(explode(' ', $str), $searchWords) != null);
OUTPUT: for 2 examples you've provided:
bool(true)
bool(false)
Update:
If string cannot be exploded using space character, then use code like this to split string on any end of word character:
var_dump(array_intersect(preg_split('~\b~', $str), $searchWords) != null);
There is always debate over what is faster so I thought I'd run some tests using different methods.
Tests Run:
strpos
preg_match with foreach loop
preg_match with regex or
indexed search with string to explode
indexed search as array (string already exploded)
Two sets of tests where run. One on a large text document (114,350 words) and one on a small text document (120 words). Within each set, all tests were run 100 times and then an average was taken. Tests did not ignore case, which doing so would have made them all faster. Test for which the index was searched were pre-indexed. I wrote the code for indexing myself, and I'm sure it was less efficient, but indexing for the large file took 17.92 seconds and for the small file it took 0.001 seconds.
Terms searched for included: gazerbeam (NOT found in the document), legally (found in the document), and target (NOT found in the document).
Results in seconds to complete a single test, sorted by speed:
Large File:
0.0000455808639526 (index without explode)
0.0009979915618897 (preg_match using regex or)
0.0011657214164734 (strpos)
0.0023632574081421 (preg_match using foreach loop)
0.0051533532142639 (index with explode)
Small File
0.000003724098205566 (strpos)
0.000005958080291748 (preg_match using regex or)
0.000012607574462891 (preg_match using foreach loop)
0.000021204948425293 (index without explode)
0.000060625076293945 (index with explode)
Notice that strpos is faster than preg_match (using regex or) for small files, but slower for large files. Other factors, such as the number of search terms will of course affect this.
Algorithms Used:
//strpos
$str = file_get_contents('text.txt');
$t = microtime(true);
foreach ($search as $word) if (strpos($str, $word)) break;
$strpos += microtime(true) - $t;
//preg_match
$str = file_get_contents('text.txt');
$t = microtime(true);
foreach ($search as $word) if (preg_match('/' . preg_quote($word) . '/', $str)) break;
$pregmatch += microtime(true) - $t;
//preg_match (regex or)
$str = file_get_contents('text.txt');
$orstr = preg_quote(implode('|', $search));
$t = microtime(true);
if preg_match('/' . $orstr . '/', $str) {};
$pregmatchor += microtime(true) - $t;
//index with explode
$str = file_get_contents('textindex.txt');
$t = microtime(true);
$ar = explode(" ", $str);
foreach ($search as $word) {
$start = 0;
$end = count($ar);
do {
$diff = $end - $start;
$pos = floor($diff / 2) + $start;
$temp = $ar[$pos];
if ($word < $temp) {
$end = $pos;
} elseif ($word > $temp) {
$start = $pos + 1;
} elseif ($temp == $word) {
$found = 'true';
break;
}
} while ($diff > 0);
}
$indexwith += microtime(true) - $t;
//index without explode (already in array)
$str = file_get_contents('textindex.txt');
$found = 'false';
$ar = explode(" ", $str);
$t = microtime(true);
foreach ($search as $word) {
$start = 0;
$end = count($ar);
do {
$diff = $end - $start;
$pos = floor($diff / 2) + $start;
$temp = $ar[$pos];
if ($word < $temp) {
$end = $pos;
} elseif ($word > $temp) {
$start = $pos + 1;
} elseif ($temp == $word) {
$found = 'true';
break;
}
} while ($diff > 0);
}
$indexwithout += microtime(true) - $t;
try this:
$string = 'Alice goes to school every day';
$words = split(" ", $string);
$searchWords = array('basket','school','tree');
for($x = 0,$l = count($words); $x < $l;) {
if(in_array($words[$x++], $searchWords)) {
//....
}
}
Below prints the frequency of number of elements found from the array in the string
function inString($str, $arr, $matches=false)
{
$str = explode(" ", $str);
$c = 0;
for($i = 0; $i<count($str); $i++)
{
if(in_array($str[$i], $arr) )
{$c++;if($matches == false)break;}
}
return $c;
}
Below link will help you : just need to customize as you required.
Check if array element exists in string
customized:
function result_arrayInString($prdterms,208){
if(arrayInString($prdterms,208)){
return true;
}else{
return false;
}
}
This may be helpful to you.