I have a comma separated list of prefixes stored in a variable
$prefixes = “fa,go,urg”;
and a word stored in another variable
$word = “good”;
Now I want to know efficient way to check if any of the prefixes stored in $prefixes is the prefix of $word or not.
My intention is
If any of the prefixes stored in $prefixes is the prefix of the word stored in $word return TRUE.
If none of the prefixes stored in $prefixes is the prefix of the word stored in $word return FALSE.
Note:- Comma separated list of prefixes is provide by user using text box.
One thing that can be done is to have the prefixes within an array, and then check if $word is present within the array $preArr using in_array
in_array
(PHP 4, PHP 5, PHP 7)
in_array — Checks if a value exists in an array
$prefixes = “fa,go,urg”;
$preArr = explode(',', $prefixes); // Convert to array
$word = “good”;
if (in_array($word, $preArr)) {
echo "Success!";
} else {
echo "Failure!";
}
The substr function can achieve the desired result. It checks for the word good in the prefixes at specified location, which is the beginning of the word.
From the PHP Manual:
substr — Return part of a string
Description
string substr ( string $string , int $start [, int $length ] )
Returns the portion of string specified by the start and length parameters.
Try this:
$prefixes = “fa,go,urg”;
$word = “good”;
$Arr[] = explode(',', $prefixes); // Convert to array
$elements = count($Arr[]); //get total elements in array
for ($i=0;$i<count;$i++) {
if (substr( $Arr(i), 0, 4 ) === $word) {
return true;
}
else {return false;}
}
Your problem can be solved by a few ways, the most programmatic method being to just do a simple check, iterate across $prefixes and check it against 0.....i where i = N - 1 and N = count($prefixes[$i])
function inPrefixArr($prefixes, $word) {
$prefixesInArray = explode(',', $prefixes);
for ($i = 0; $i < count($prefixesInArray); i++) {
if (count($prefixesInArray[$i]) <= count($word)) {
if ($prefixesInArray[$i] == substr($word, 0, count($prefixesInArray[$i]))) {
return True;
}
}
}
return False
}
This checks if the any of the prefixes are a prefix of the word given in O(mn) time where m is the max length of some prefix in the array given. It is also the fastest and most space optimal solution that can be found.
As it seems you weren't asking for a theoretical/CS question, there are other interesting ways to implement this in other data structures which can yield better runtimes if you do this repeatedly.
I have the following code routine, which is preg_match ing xml elements and printing the attributes of those elements.
However, in some of the tags, the content does not appear on one line (the SCRIPT tag), and therefore doesnt get matched.
I am wondering how to look ahead and gather all the lines until the closing tag "/>" ?
Is it possible to use the # character somewhere in the preg_match, to allow new lines?
I'm not even sure about how to go about resolving this. I've done a PHP sandbox so the code can be tested online:
http://sandbox.onlinephpfunctions.com/code/f96daef33fb49179eee30250ded81af6a8e5c567
If I remove all the data in the script tag, all apart from the first line, then it correctly outputs the array.
$file = ' <TOPTAG class="Menu" text="FCLPHP" >
<TAG1 name="contain=" />
<SCRIPT name="check()" script="if(B3||B4||B5 == 1){
do(ABC,0);
do(BCD,1);" />
</WINDOW>
';
//split the string into an array based on new line
$lines = explode("\n", $file);
//count the number of lines
$linesLength = count($lines);
for($index = 0; $index < $linesLength; $index++){
//reads all element atrributes from the TOPTAG element
$reads = element_attributes('TOPTAG',$lines[$index]);
//reads all element atrributes from the SCRIPT element
$scripts = element_attributes('SCRIPT',$lines[$index]);
//prints the script tag attributes
print_r($scripts);
}
function element_attributes($element_name, $xml) {
if ($xml == false) {
return false;
}
// Grab the string of attributes inside an element tag.
$found = preg_match('#<'.$element_name.
'\s+([^>]+(?:"|\'))\s?/?>#',
$xml, $matches);
if ($found == 1) {
$attribute_array = array();
$attribute_string = $matches[1];
// Match attribute-name attribute-value pairs.
$found = preg_match_all(
'#([^\s=]+)\s*=\s*(\'[^<\']*\'|"[^<"]*")#',
$attribute_string, $matches, PREG_SET_ORDER);
if ($found != 0) {
// Create an associative array that matches attribute
// names to attribute values.
foreach ($matches as $attribute) {
$attribute_array[$attribute[1]] =
substr($attribute[2], 1, -1);
}
return $attribute_array;
}
}
// Attributes either weren't found, or couldn't be extracted
// by the regular expression.
return false;
}
Your regexp operates across multiple lines. The problem is that you're only using it on one line at a time, so it never sees the continuation. Don't split the file into lines, just work with it as a single string.
$reads = element_attributes('TOPTAG',$file);
$scripts = element_attributes('SCRIPT',$file);
Is there an easy way to parse the following data that I will post below. The data comes from the web.
I was using the $rows = explode("\n", $txt_file); then the $parts = explode('=', $line_of_text); to get the key name and values. However, I don't know how to handle the extra information that I do not want.
Additionally, I do not know how to get rid of the extra spaces. The file seems to be made for some kind of easy parsing. I have looked all over this site to find a solution. However, this data is quite different than the examples I have found on this site.
# This file holds all the timelines available at this time.
# All lines starting with # is ignored by parser...
#
STARTINFO
description = Rubi-Ka 2
displayname = Rimor (Rubi-Ka 2)
connect = cm.d2.funcom.com
ports = 7502
url =
version = 18.5.4
ENDINFO
STARTINFO
description = Rubi-Ka 1
displayname = Atlantean (Rubi-Ka 1)
connect = cm.d1.funcom.com
ports = 7501
url =
version = 18.5.4
ENDINFO
You can use the trim function to get rid of the whitespace.
To only keep the columns you want, you can store their keys in an array, and make a check against it when parsing.
Here's an example (albeit rather verbose).
<?
$lines = explode("\n", $data);
$result = array();
$count = 0;
// an array of the keys we want to keep
// I have the columns as keys rather then values for faster lookup
$cols_to_keep = array( 'url'=>null, 'description'=>null, 'ports'=>null, 'displayname' => null);
foreach($lines as $line)
{
//skip comments and empty lines
if(empty($line) || $line[0] == '#')
{ continue; }
//if we start a new block, initalize result array for it
if(trim($line) == 'STARTINFO')
{
$result[$count] = array();
continue;
}
// if we reach ENDINFO increment count
if(trim($line) == 'ENDINFO')
{
$count++;
continue;
}
//here we can split into key - value
$parts = explode('=', $line);
//and if it's in our cols_to_keep, we add it on
if(array_key_exists(trim($parts[0]), $cols_to_keep))
{ $result[$count][ trim($parts[0]) ] = trim( $parts[1] ); }
}
print_r($result);
?>
how to find out if csv file fields are tab delimited or comma delimited. I need php validation for this. Can anyone plz help. Thanks in advance.
It's too late to answer this question but hope it will help someone.
Here's a simple function that will return a delimiter of a file.
function getFileDelimiter($file, $checkLines = 2){
$file = new SplFileObject($file);
$delimiters = array(
',',
'\t',
';',
'|',
':'
);
$results = array();
$i = 0;
while($file->valid() && $i <= $checkLines){
$line = $file->fgets();
foreach ($delimiters as $delimiter){
$regExp = '/['.$delimiter.']/';
$fields = preg_split($regExp, $line);
if(count($fields) > 1){
if(!empty($results[$delimiter])){
$results[$delimiter]++;
} else {
$results[$delimiter] = 1;
}
}
}
$i++;
}
$results = array_keys($results, max($results));
return $results[0];
}
Use this function as shown below:
$delimiter = getFileDelimiter('abc.csv'); //Check 2 lines to determine the delimiter
$delimiter = getFileDelimiter('abc.csv', 5); //Check 5 lines to determine the delimiter
P.S I have used preg_split() instead of explode() because explode('\t', $value) won't give proper results.
UPDATE: Thanks for #RichardEB pointing out a bug in the code. I have updated this now.
Here's what I do.
Parse the first 5 lines of a CSV file
Count the number of delimiters [commas, tabs, semicolons and colons] in each line
Compare the number of delimiters in each line. If you have a properly formatted CSV, then one of the delimiter counts will match in each row.
This will not work 100% of the time, but it is a decent starting point. At minimum, it will reduce the number of possible delimiters (making it easier for your users to select the correct delimiter).
/* Rearrange this array to change the search priority of delimiters */
$delimiters = array('tab' => "\t",
'comma' => ",",
'semicolon' => ";"
);
$handle = file( $file ); # Grabs the CSV file, loads into array
$line = array(); # Stores the count of delimiters in each row
$valid_delimiter = array(); # Stores Valid Delimiters
# Count the number of Delimiters in Each Row
for ( $i = 1; $i < 6; $i++ ){
foreach ( $delimiters as $key => $value ){
$line[$key][$i] = count( explode( $value, $handle[$i] ) ) - 1;
}
}
# Compare the Count of Delimiters in Each line
foreach ( $line as $delimiter => $count ){
# Check that the first two values are not 0
if ( $count[1] > 0 and $count[2] > 0 ){
$match = true;
$prev_value = '';
foreach ( $count as $value ){
if ( $prev_value != '' )
$match = ( $prev_value == $value and $match == true ) ? true : false;
$prev_value = $value;
}
} else {
$match = false;
}
if ( $match == true ) $valid_delimiter[] = $delimiter;
}//foreach
# Set Default delimiter to comma
$delimiter = ( $valid_delimiter[0] != '' ) ? $valid_delimiter[0] : "comma";
/* !!!! This is good enough for my needs since I have the priority set to "tab"
!!!! but you will want to have to user select from the delimiters in $valid_delimiter
!!!! if multiple dilimiter counts match
*/
# The Delimiter for the CSV
echo $delimiters[$delimiter];
There is no 100% reliable way to detemine this. What you can do is
If you have a method to validate the fields you read, try to read a few fields using either separator and validate against your method. If it breaks, use another one.
Count the occurrence of tabs or commas in the file. Usually one is significantly higher than the other
Last but not least: Ask the user, and allow him to override your guesses.
I'm just counting the occurrences of the different delimiters in the CSV file, the one with the most should probably be the correct delimiter:
//The delimiters array to look through
$delimiters = array(
'semicolon' => ";",
'tab' => "\t",
'comma' => ",",
);
//Load the csv file into a string
$csv = file_get_contents($file);
foreach ($delimiters as $key => $delim) {
$res[$key] = substr_count($csv, $delim);
}
//reverse sort the values, so the [0] element has the most occured delimiter
arsort($res);
reset($res);
$first_key = key($res);
return $delimiters[$first_key];
In my situation users supply csv files which are then entered into an SQL database. They may save an Excel Spreadsheet as comma or tab delimited files. A program converting the spreadsheet to SQL needs to automatically identify whether fields are tab separated or comma
Many Excel csv export have field headings as the first line. The heading test is unlikely to contain commas except as a delimiter. For my situation I counted the commas and tabs of the first line and use that with the greater number to determine if it is csv or tab
Thanks for all your inputs, I made mine using your tricks : preg_split, fgetcsv, loop, etc.
But I implemented something that was surprisingly not here, the use of fgets instead of reading the whole file, way better if the file is heavy!
Here's the code :
ini_set("auto_detect_line_endings", true);
function guessCsvDelimiter($filePath, $limitLines = 5) {
if (!is_readable($filePath) || !is_file($filePath)) {
return false;
}
$delimiters = array(
'tab' => "\t",
'comma' => ",",
'semicolon' => ";"
);
$fp = fopen($filePath, 'r', false);
$lineResults = array(
'tab' => array(),
'comma' => array(),
'semicolon' => array()
);
$lineIndex = 0;
while (!feof($fp)) {
$line = fgets($fp);
foreach ($delimiters as $key=>$delimiter) {
$lineResults[$key][$lineIndex] = count (fgetcsv($fp, 1024, $delimiter)) - 1;
}
$lineIndex++;
if ($lineIndex > $limitLines) break;
}
fclose($fp);
// Calculating average
foreach ($lineResults as $key=>$entry) {
$lineResults[$key] = array_sum($entry)/count($entry);
}
arsort($lineResults);
reset($lineResults);
return ($lineResults[0] !== $lineResults[1]) ? $delimiters[key($lineResults)] : $delimiters['comma'];
}
I used #Jay Bhatt's solution for finding out a csv file's delimiter, but it didn't work for me, so I applied a few fixes and comments for the process to be more understandable.
See my version of #Jay Bhatt's function:
function decide_csv_delimiter($file, $checkLines = 10) {
// use php's built in file parser class for validating the csv or txt file
$file = new SplFileObject($file);
// array of predefined delimiters. Add any more delimiters if you wish
$delimiters = array(',', '\t', ';', '|', ':');
// store all the occurences of each delimiter in an associative array
$number_of_delimiter_occurences = array();
$results = array();
$i = 0; // using 'i' for counting the number of actual row parsed
while ($file->valid() && $i <= $checkLines) {
$line = $file->fgets();
foreach ($delimiters as $idx => $delimiter){
$regExp = '/['.$delimiter.']/';
$fields = preg_split($regExp, $line);
// construct the array with all the keys as the delimiters
// and the values as the number of delimiter occurences
$number_of_delimiter_occurences[$delimiter] = count($fields);
}
$i++;
}
// get key of the largest value from the array (comapring only the array values)
// in our case, the array keys are the delimiters
$results = array_keys($number_of_delimiter_occurences, max($number_of_delimiter_occurences));
// in case the delimiter happens to be a 'tab' character ('\t'), return it in double quotes
// otherwise when using as delimiter it will give an error,
// because it is not recognised as a special character for 'tab' key,
// it shows up like a simple string composed of '\' and 't' characters, which is not accepted when parsing csv files
return $results[0] == '\t' ? "\t" : $results[0];
}
I personally use this function for helping automatically parse a file with PHPExcel, and it works beautifully and fast.
I recommend parsing at least 10 lines, for the results to be more accurate. I personally use it with 100 lines, and it is working fast, no delays or lags. The more lines you parse, the more accurate the result gets.
NOTE: This is just a modifed version of #Jay Bhatt's solution to the question. All credits goes to #Jay Bhatt.
When I output a TSV file I author the tabs using \t the same method one would author a line break like \n so that being said I guess a method could be as follows:
<?php
$mysource = YOUR SOURCE HERE, file_get_contents() OR HOWEVER YOU WISH TO GET THE SOURCE;
if(strpos($mysource, "\t") > 0){
//We have a tab separator
}else{
// it might be CSV
}
?>
I Guess this may not be the right manner, because you could have tabs and commas in the actual content as well. It's just an idea. Using regular expressions may be better, although I am not too clued up on that.
you can simply use the fgetcsv(); PHP native function in this way:
function getCsvDelimeter($file)
{
if (($handle = fopen($file, "r")) !== FALSE) {
$delimiters = array(',', ';', '|', ':'); //Put all that need check
foreach ($delimiters AS $item) {
//fgetcsv() return array with unique index if not found the delimiter
if (count(fgetcsv($handle, 0, $item, '"')) > 1) {
$delimiter = $item;
break;
}
}
}
return (isset($delimiter) ? $delimiter : null);
}
Aside from the trivial answer that c sv files are always comma-separated - it's in the name, I don't think you can come up with any hard rules. Both TSV and CSV files are sufficiently loosely specified that you can come up with files that would be acceptable as either.
A\tB,C
1,2\t3
(Assuming \t == TAB)
How would you decide whether this is TSV or CSV?
You also can use fgetcsv (http://php.net/manual/en/function.fgetcsv.php) passing it a delimiter parameter. If the function returns false it means that the $delimiter parameter wasn't the right one
sample to check if the delimiter is ';'
if (($data = fgetcsv($your_csv_handler, 1000, ';')) !== false) { $csv_delimiter = ';'; }
How about something simple?
function findDelimiter($filePath, $limitLines = 5){
$file = new SplFileObject($filePath);
$delims = $file->getCsvControl();
return $delims[0];
}
This is my solution.
Its works if you know how many columns you expect.
Finally, the separator character is the $actual_separation_character
$separator_1=",";
$separator_2=";";
$separator_3="\t";
$separator_4=":";
$separator_5="|";
$separator_1_number=0;
$separator_2_number=0;
$separator_3_number=0;
$separator_4_number=0;
$separator_5_number=0;
/* YOU NEED TO CHANGE THIS VARIABLE */
// Expected number of separation character ( 3 colums ==> 2 sepearation caharacter / row )
$expected_separation_character_number=2;
$file = fopen("upload/filename.csv","r");
while(! feof($file)) //read file rows
{
$row= fgets($file);
$row_1_replace=str_replace($separator_1,"",$row);
$row_1_length=strlen($row)-strlen($row_1_replace);
if(($row_1_length==$expected_separation_character_number)or($expected_separation_character_number==0)){
$separator_1_number=$separator_1_number+$row_1_length;
}
$row_2_replace=str_replace($separator_2,"",$row);
$row_2_length=strlen($row)-strlen($row_2_replace);
if(($row_2_length==$expected_separation_character_number)or($expected_separation_character_number==0)){
$separator_2_number=$separator_2_number+$row_2_length;
}
$row_3_replace=str_replace($separator_3,"",$row);
$row_3_length=strlen($row)-strlen($row_3_replace);
if(($row_3_length==$expected_separation_character_number)or($expected_separation_character_number==0)){
$separator_3_number=$separator_3_number+$row_3_length;
}
$row_4_replace=str_replace($separator_4,"",$row);
$row_4_length=strlen($row)-strlen($row_4_replace);
if(($row_4_length==$expected_separation_character_number)or($expected_separation_character_number==0)){
$separator_4_number=$separator_4_number+$row_4_length;
}
$row_5_replace=str_replace($separator_5,"",$row);
$row_5_length=strlen($row)-strlen($row_5_replace);
if(($row_5_length==$expected_separation_character_number)or($expected_separation_character_number==0)){
$separator_5_number=$separator_5_number+$row_5_length;
}
} // while(! feof($file)) END
fclose($file);
/* THE FILE ACTUAL SEPARATOR (delimiter) CHARACTER */
/* $actual_separation_character */
if ($separator_1_number==max($separator_1_number,$separator_2_number,$separator_3_number,$separator_4_number,$separator_5_number)){$actual_separation_character=$separator_1;}
else if ($separator_2_number==max($separator_1_number,$separator_2_number,$separator_3_number,$separator_4_number,$separator_5_number)){$actual_separation_character=$separator_2;}
else if ($separator_3_number==max($separator_1_number,$separator_2_number,$separator_3_number,$separator_4_number,$separator_5_number)){$actual_separation_character=$separator_3;}
else if ($separator_4_number==max($separator_1_number,$separator_2_number,$separator_3_number,$separator_4_number,$separator_5_number)){$actual_separation_character=$separator_4;}
else if ($separator_5_number==max($separator_1_number,$separator_2_number,$separator_3_number,$separator_4_number,$separator_5_number)){$actual_separation_character=$separator_5;}
else {$actual_separation_character=";";}
/*
if the number of columns more than what you expect, do something ...
*/
if ($expected_separation_character_number>0){
if ($separator_1_number==0 and $separator_2_number==0 and $separator_3_number==0 and $separator_4_number==0 and $separator_5_number==0){/* do something ! more columns than expected ! */}
}
If you have a very large file example in GB, head the first few line, put in a temporary file. Open the temporary file in vi
head test.txt > te1
vi te1
Easiest way I answer this is open it in a plain text editor, or in TextMate.
I want to be able to parse file paths like this one:
/var/www/index.(htm|html|php|shtml)
into an ordered array:
array("htm", "html", "php", "shtml")
and then produce a list of alternatives:
/var/www/index.htm
/var/www/index.html
/var/www/index.php
/var/www/index.shtml
Right now, I have a preg_match statement that can split two alternatives:
preg_match_all ("/\(([^)]*)\|([^)]*)\)/", $path_resource, $matches);
Could somebody give me a pointer how to extend this to accept an unlimited number of alternatives (at least two)? Just regarding the regular expression, the rest I can deal with.
The rule is:
The list needs to start with a ( and close with a )
There must be one | in the list (i.e. at least two alternatives)
Any other occurrence(s) of ( or ) are to remain untouched.
Update: I need to be able to also deal with multiple bracket pairs such as:
/var/(www|www2)/index.(htm|html|php|shtml)
sorry I didn't say that straight away.
Update 2: If you're looking to do what I'm trying to do in the filesystem, then note that glob() already brings this functionality out of the box. There is no need to implement a custom solutiom. See #Gordon's answer below for details.
I think you're looking for:
/(([^|]+)(|([^|]+))+)/
Basically, put the splitter '|' into a repeating pattern.
Also, your words should be made up 'not pipes' instead of 'not parens', per your third requirement.
Also, prefer + to * for this problem. + means 'at least one'. * means 'zero or more'.
Not exactly what you are asking, but what's wrong with just taking what you have to get the list (ignoring the |s), putting it into a variable and then explodeing on the |s? That would give you an array of however many items there were (including 1 if there wasn't a | present).
Non-regex solution :)
<?php
$test = '/var/www/index.(htm|html|php|shtml)';
/**
*
* #param string $str "/var/www/index.(htm|html|php|shtml)"
* #return array "/var/www/index.htm", "/var/www/index.php", etc
*/
function expand_bracket_pair($str)
{
// Only get the very last "(" and ignore all others.
$bracketStartPos = strrpos($str, '(');
$bracketEndPos = strrpos($str, ')');
// Split on ",".
$exts = substr($str, $bracketStartPos, $bracketEndPos - $bracketStartPos);
$exts = trim($exts, '()|');
$exts = explode('|', $exts);
// List all possible file names.
$names = array();
$prefix = substr($str, 0, $bracketStartPos);
$affix = substr($str, $bracketEndPos + 1);
foreach ($exts as $ext)
{
$names[] = "{$prefix}{$ext}{$affix}";
}
return $names;
}
function expand_filenames($input)
{
$nbBrackets = substr_count($input, '(');
// Start with the last pair.
$sets = expand_bracket_pair($input);
// Now work backwards and recurse for each generated filename set.
for ($i = 0; $i < $nbBrackets; $i++)
{
foreach ($sets as $k => $set)
{
$sets = array_merge(
$sets,
expand_bracket_pair($set)
);
}
}
// Clean up.
foreach ($sets as $k => $set)
{
if (false !== strpos($set, '('))
{
unset($sets[$k]);
}
}
$sets = array_unique($sets);
sort($sets);
return $sets;
}
var_dump(expand_filenames('/(a|b)/var/(www|www2)/index.(htm|html|php|shtml)'));
Maybe I'm still not getting the question, but my assumption is you are running through the filesystem until you hit one of the files, in which case you could do
$files = glob("$path/index.{htm,html,php,shtml}", GLOB_BRACE);
The resulting array will contain any file matching your extensions in $path or none. If you need to include files by a specific extension order, you can foreach over the array with an ordered list of extensions, e.g.
foreach(array('htm','html','php','shtml') as $ext) {
foreach($files as $file) {
if(pathinfo($file, PATHINFO_EXTENSION) === $ext) {
// do something
}
}
}
Edit: and yes, you can have multiple curly braces in glob.
The answer is given, but it's a funny puzzle and i just couldn't resist
function expand_filenames2($str) {
$r = array($str);
$n = 0;
while(preg_match('~(.*?) \( ( \w+ \| [\w|]+ ) \) (.*) ~x', $r[$n++], $m)) {
foreach(explode('|', $m[2]) as $e)
$r[] = $m[1] . $e . $m[3];
}
return array_slice($r, $n - 1);
}
print_r(expand_filenames2('/(a|b)/var/(ignore)/(www|www2)/index.(htm|html|php|shtml)!'));
maybe this explains a bit why we like regexps that much ;)