CXXI. String Functions

Wstęp

These functions all manipulate strings in various ways. Some more specialized sections can be found in the regular expression and URL handling sections.

For information on how strings behave, especially with regard to usage of single quotes, double quotes, and escape sequences, see the Strings entry in the Types section of the manual.

Wymagania

Do zbudowania tego rozszerzenia nie są wymagane żadne zewnętrzne biblioteki.

Instalacja

By używać tych funkcji, nie trzeba niczego instalować. Są one częścią jądra PHP.

Stałe predefinopwane

Poniższe stałe są zdefiniowane w tym rozszerzeniu i stają się dostępne, gdy rozszerzenie jest dokompilowane do PHP, lub załadowane dynamicznie przy starcie.

CRYPT_SALT_LENGTH integer
CRYPT_STD_DES integer
CRYPT_EXT_DES integer
CRYPT_MD5 integer
CRYPT_BLOWFISH integer
HTML_SPECIALCHARS (integer)
HTML_ENTITIES (integer)
ENT_COMPAT (integer)
ENT_QUOTES (integer)
ENT_NOQUOTES (integer)
CHAR_MAX (integer)
LC_CTYPE (integer)
LC_NUMERIC (integer)
LC_TIME (integer)
LC_COLLATE (integer)
LC_MONETARY (integer)
LC_ALL (integer)
LC_MESSAGES (integer)
STR_PAD_LEFT (integer)
STR_PAD_RIGHT (integer)
STR_PAD_BOTH (integer)

Patrz także

For even more powerful string handling and manipulating functions take a look at the POSIX regular expression functions and the Perl compatible regular expression functions.

Spis treści
addcslashes -- Quote string with slashes in a C style
addslashes -- Quote string with slashes
bin2hex -- Convert binary data into hexadecimal representation
chop -- Alias of rtrim()
chr -- Return a specific character
chunk_split -- Split a string into smaller chunks
convert_cyr_string -- Convert from one Cyrillic character set to another
convert_uudecode -- Decode a uuencoded string
convert_uuencode -- Uuencode a string
count_chars -- Return information about characters used in a string
crc32 -- Calculates the crc32 polynomial of a string
crypt -- One-way string encryption (hashing)
echo -- Output one or more strings
explode -- Split a string by string
fprintf -- Write a formatted string to a stream
get_html_translation_table -- Returns the translation table used by htmlspecialchars() and htmlentities()
hebrev -- Convert logical Hebrew text to visual text
hebrevc -- Convert logical Hebrew text to visual text with newline conversion
html_entity_decode -- Convert all HTML entities to their applicable characters
htmlentities -- Convert all applicable characters to HTML entities
htmlspecialchars_decode -- Convert special HTML entities back to characters
htmlspecialchars -- Convert special characters to HTML entities
implode -- Join array elements with a string
join -- Alias of implode()
levenshtein -- Calculate Levenshtein distance between two strings
localeconv -- Get numeric formatting information
ltrim -- Strip whitespace (or other characters) from the beginning of a string
md5_file -- Calculates the md5 hash of a given file
md5 -- Calculate the md5 hash of a string
metaphone -- Calculate the metaphone key of a string
money_format -- Formats a number as a currency string
nl_langinfo -- Query language and locale information
nl2br -- Inserts HTML line breaks before all newlines in a string
number_format -- Format a number with grouped thousands
ord -- Return ASCII value of character
parse_str -- Parses the string into variables
print -- Output a string
printf -- Output a formatted string
quoted_printable_decode -- Convert a quoted-printable string to an 8 bit string
quotemeta -- Quote meta characters
rtrim -- Strip whitespace (or other characters) from the end of a string
setlocale -- Set locale information
sha1_file -- Calculate the sha1 hash of a file
sha1 -- Calculate the sha1 hash of a string
similar_text -- Calculate the similarity between two strings
soundex -- Calculate the soundex key of a string
sprintf -- Return a formatted string
sscanf -- Parses input from a string according to a format
str_ireplace -- Case-insensitive version of str_replace().
str_pad -- Pad a string to a certain length with another string
str_repeat -- Repeat a string
str_replace -- Replace all occurrences of the search string with the replacement string
str_rot13 -- Perform the rot13 transform on a string
str_shuffle -- Randomly shuffles a string
str_split -- Convert a string to an array
str_word_count -- Return information about words used in a string
strcasecmp -- Binary safe case-insensitive string comparison
strchr -- Alias of strstr()
strcmp -- Binary safe string comparison
strcoll -- Locale based string comparison
strcspn -- Find length of initial segment not matching mask
strip_tags -- Strip HTML and PHP tags from a string
stripcslashes -- Un-quote string quoted with addcslashes()
stripos -- Find position of first occurrence of a case-insensitive string
stripslashes -- Un-quote string quoted with addslashes()
stristr -- Case-insensitive strstr()
strlen -- Get string length
strnatcasecmp -- Case insensitive string comparisons using a "natural order" algorithm
strnatcmp -- String comparisons using a "natural order" algorithm
strncasecmp -- Binary safe case-insensitive string comparison of the first n characters
strncmp -- Binary safe string comparison of the first n characters
strpbrk -- Search a string for any of a set of characters
strpos -- Find position of first occurrence of a string
strrchr -- Find the last occurrence of a character in a string
strrev -- Reverse a string
strripos -- Find position of last occurrence of a case-insensitive string in a string
strrpos -- Find position of last occurrence of a char in a string
strspn -- Find length of initial segment matching mask
strstr -- Find first occurrence of a string
strtok -- Tokenize string
strtolower -- Make a string lowercase
strtoupper -- Make a string uppercase
strtr -- Translate certain characters
substr_compare -- Binary safe optionally case insensitive comparison of 2 strings from an offset, up to length characters
substr_count -- Count the number of substring occurrences
substr_replace -- Replace text within a portion of a string
substr -- Return part of a string
trim -- Strip whitespace (or other characters) from the beginning and end of a string
ucfirst -- Make a string's first character uppercase
ucwords -- Uppercase the first character of each word in a string
vfprintf -- Write a formatted string to a stream
vprintf -- Output a formatted string
vsprintf -- Return a formatted string
wordwrap -- Wraps a string to a given number of characters using a string break character

User Contributed Notes


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.



<?

$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;



}



?>


Updated; used to test for input as an array, should have been a string, added some validation of the input while I was at it.  Enjoy.



<?php

/*----------        Directory Tree to Array        ----------//

  Takes base directory, returns an associative array

       containing each directory name as an associative key

       and each file as an indexed entry in the appropriate

       directory.

  If no path is provided, it uses the current directory

  If $style == 1, it will return a sorted, non-associative

       array



  By Peter Dolan

  www.peterd.net

  Updated 2005-10-12



  Use it as much as you like for whatever

  For my own entertainment, please let me know if you do

//-----------------------------------------------------------*/

function dirTreeToArray( $path = "./", $style="0" ) {

     if ( !is_string($path) or !($style==0 or $style==1) ) die("Improper arguments in function dirTreeToArray(string \$path, \$style = {0, 1})");

     else {

        $path = trim($path);

        $path = str_replace("\\", "/", $path);

        if( '/' == $path{strlen($path)-1} || '\'' == $path{strlen($path)-1} ) $path = substr($path, 0, strlen($path)-1);

     }

     $tree = array();

     $arrayPointer = & $tree;

   if ( $handle = opendir($path) ) {

       while ( $fileName = readdir($handle) ) {

             if ( $fileName != "." and $fileName != ".." ) {

                       $newPath = "$path/$fileName";        // Used for testing directory or file property

                 if ( is_dir($newPath) ) {

                   $dummyPointer = & $arrayPointer;        // Save the current pointer

                     if ( $style == 0 ) $arrayPointer = & $arrayPointer[$fileName];    // Drop the pointer into a subdirectory

                     elseif ( $style == 1 ) $arrayPointer = & $arrayPointer[];        // Drop the pointer into a subdirectory

                     $arrayPointer = dirTreeToArray($newPath, $style);            // Process the new subdirectory

                   if ( $style == 1 ) sort($arrayPointer);    // Sort it if we're in a non-associative mode

                     $arrayPointer = & $dummyPointer;        // Bring the pointer back up a level

               }

                 elseif ( is_file($newPath) ) $arrayPointer[] = $fileName;    // Enter the files

           }

       }

               return $tree;

   }

   else die("Failed to open directory $path in function dirTreeToArray(string \$path, \$style = {0, 1})");

}

?>


<?php

/**

Utility class: static methods for cleaning & escaping untrusted (i.e.

user-supplied) strings.



Any string can (usually) be thought of as being in one of these 'modes':



pure = what the user actually typed / what you want to see on the page /

       what is actually stored in the DB

gpc  = incoming GET, POST or COOKIE data

sql  = escaped for passing safely to RDBMS via SQL (also, data from DB

       queries and file reads if you have magic_quotes_runtime on--which

       is rare)

html = safe for html display (htmlentities applied)



Always knowing what mode your string is in--using these methods to

convert between modes--will prevent SQL injection and cross-site scripting.



This class refers to its own namespace (so it can work in PHP 4--there is no

self keyword until PHP 5). Do not change the name of the class w/o changing

all the internal references.



Example usage: a POST value that you want to query with:

$username = Str::gpc2sql($_POST['username']);

*/



//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);

    }

}

?>