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A.2c. Alphabetical Listing of PHP Functions (j-q)

join

string join(array strings,string separator)

This function is an alias of implode( ).

key

mixed key(array array)

Returns the key for the element currently pointed to by the internal array pointer.

key_exists

bool key_exists(mixed key, array array)

Returns true if array contains a key with the value key. If no such key is available, returns false.

krsort

int krsort(array array[, int flags])

Sorts an array by key in reverse order, maintaining the keys for the array values. The optional second parameter contains additional sorting flags. See Chapter 5 and sort for more information on using this function.

ksort

int ksort(array array[, int flags])

Sorts an array by key, maintaining the keys for the array values. The optional second parameter contains additional sorting flags. See Chapter 5 and sort for more information on using this function.

lcg_value

double lcg_value( )

Returns a pseudorandom number between 0 and 1, inclusive, using a linear congruential- number generator.

levenshtein

int levenshtein(string one, string two[, int insert, int replace, int delete])
int levenshtein(string one, string two[, mixed callback])

Calculates the Levenshtein distance between two strings; this is the number of characters you have to replace, insert, or delete to transform one into two. By default, replacements, inserts, and deletes have the same cost, but you can specify different costs with insert, replace, and delete. In the second form, you provide a callback to calculate the cost of an operation.

link

int link(string path, string new)

Creates a hard link to path at the path new. Returns true if the link was successfully created and false if not.

linkinfo

int linkinfo(string path)

Returns true if path is a link and if the file referenced by path exists. Returns false if path is not a link, if the file referenced by it does not exist, or if an error occurs.

list

void list(mixed value1[, ... valueN])

Assigns a set of variables from elements in an array. For example:

list($first, $second) = array(1, 2); // $first = 1, $second = 2

Note: list is actually a language construct.

localeconv

array localeconv( )

Returns an associative array of information about the current locale's numeric and monetary formatting. The array contains the following elements:

 

decimal_point

 

Decimal-point character

 

thousands_sep

 

Separator character for thousands

 

grouping

 

Array of numeric groupings; indicates where the number should be separated using the thousands separator character

 

int_curr_symbol

 

International currency symbol (e.g., "USD")

 

currency_symbol

 

Local currency symbol (e.g., "$")

 

mon_decimal_point

 

Decimal-point character for monetary values

 

mon_thousands_sep

 

Separator character for thousands in monetary values

 

positive_sign

 

Sign for positive values

 

negative_sign

 

Sign for negative values

 

int_frac_digits

 

International fractional digits

 

frac_digits

 

Local fractional digits

 

p_cs_precedes

 

true if the local currency symbol precedes a positive value; false if it follows the value

 

p_sep_by_space

 

true if a space separates the local currency symbol from a positive value

 

p_sign_posn

 

0 if parentheses surround the value and currency symbol for positive values, 1 if the sign precedes the currency symbol and value, 2 if the sign follows the currency symbol and value, 3 if the sign precedes the currency symbol, and 4 if the sign follows the currency symbol

 

n_cs_precedes

 

true if the local currency symbol precedes a negative value; false if it follows the value

 

n_sep_by_space

 

true if a space separates the local currency symbol from a negative value

 

n_sign_posn

 

0 if parentheses surround the value and currency symbol for negative values, 1 if the sign precedes the currency symbol and value, 2 if the sign follows the currency symbol and value, 3 if the sign precedes the currency symbol, and 4 if the sign follows the currency symbol

localtime

array localtime([int timestamp[, bool associative])

Returns an array of values as given by the C function of the same name. The first argument is the timestamp; if the second argument is provided and is true, the values are returned as an associative array. If the second argument is not provided or is false, a numeric array is returned. The keys and values returned are:

 

tm_sec

 

Seconds

 

tm_min

 

Minutes

 

tm_hour

 

Hour

 

tm_mday

 

Day of the month

 

tm_mon

 

Month of the year

 

tm_year

 

Number of years since 1900

 

tm_wday

 

Day of the week

 

tm_yday

 

Day of the year

 

tm_isdst

 

1 if Daylight Savings Time was in effect at the date and time

If a numeric array is returned, the values are in the order given above.

log

double log(double number)

Returns the natural log of number.

log10

double log10(double number)

Returns the base-10 logarithm of number.

long2ip

string long2ip(int address)

Converts an IPv4 address to a dotted (standard format) address.

lstat

array lstat(string path)

Returns an associative array of information about the file path. If path is a symbolic link, information about path is returned, rather than information about the file to which path points. See fstat for a list of the values returned and their meanings.

ltrim

string ltrim(string string[, string characters])

Returns string with all characters in characters stripped from the beginning. If characters is not specified, the characters stripped are \n, \r, \t, \v, \0, and spaces.

mail

bool mail(string recipient, string subject, string message[, string headers
          [, string parameters]])

Sends message to recipient via email with the subject subject and returns true if the message was successfully sent or false if it wasn't. If given, headers is added to the end of the headers generated for the message, allowing you to add cc:, bcc:, and other headers. To add multiple headers, separate them with \n characters (or \r\n characters on Windows servers). Finally, if specified, parameters is added to the parameters of the call to the mailer program used to send the mail.

max

mixed max(mixed value1[, mixed value2[, ... mixed valueN]])

If value1 is an array, returns the largest number found in the values of the array. If not, returns the largest number found in the arguments.

md5

string md5(string string)

Calculates the MD5 hash of string and returns it.

metaphone

string metaphone(string string, int max_phonemes)

Calculates the metaphone key for string. The maximum number of phonemes to use in calculating the value is given in max_phonemes. Similar-sounding English words generate the same key.

method_exists

bool method_exists(object object, string name)

Returns true if the object contains a method with the name given in the second parameter or false otherwise. The method may be defined in the class of which the object is an instance, or in any superclass of that class.

microtime

string microtime( )

Returns a string in the format "microseconds seconds", where seconds is the number of seconds since the Unix epoch, and microseconds is the microseconds portion of the time since the Unix epoch.

min

mixed min(mixed value1[, mixed value2[, ... mixed valueN]])

If value1 is an array, returns the smallest number found in the values of the array. If not, returns the smallest number found in the arguments.

mkdir

int mkdir(string path, int mode)

Creates the directory path with mode permissions. The mode is expected to be an octal number, such as 0755. An integer value such as 755 or a string value such as "u+x" will not work as expected. Returns true if the operation was successful and false if not.

mktime

int mktime(int hours, int minutes, int seconds, int month, int day, int year
           [, int is_dst])

Returns the Unix timestamp value corresponding to the parameters, which are supplied in the order hours, minutes, seconds, month, day, year, and (optionally) whether the value is in Daylight Savings Time. This timestamp is the number of seconds elapsed between the Unix epoch ( January 1, 1970) and the given date and time.

The order of the parameters is different than that of the standard Unix mktime( ) call, to make it simpler to leave out unneeded arguments. Any arguments left out are given the current local date and time.

move_uploaded_file

bool move_uploaded_file(string from, string to)

Moves the file from to the new location to. The function moves the file only if from was uploaded by an HTTP POST. If from does not exist or is not an uploaded file, or if any other error occurs, false is returned; if not, if the operation was successful, true is returned.

mt_getrandmax

int mt_getrandmax( )

Returns the largest value that can be returned by mt_rand( ).

mt_rand

int mt_rand([int min, int max])

Returns a random number from min to max, inclusive, generated using the Mersenne Twister pseudorandom number generator. If min and max are not provided, returns a random number from 0 to the value returned by mt_getrandmax( ).

mt_srand

void mt_srand(int seed)

Seeds the Mersenne Twister generator with seed. You should call this function with a varying number, such as that returned by time( ), before making calls to mt_rand( ).

natcasesort

void natcasesort(array array)

Sorts the elements in the given array using a case-insensitive "natural order" algorithm; see natsort for more information.

natsort

void natsort(array array)

Sorts the values of the array using "natural order"; numeric values are sorted in the manner expected by language, rather than the often bizarre order in which computers insist on putting them (ASCII ordered). For example:

$array = array("1.jpg", "4.jpg", "12.jpg", "2,.jpg", "20.jpg");
$first = sort($array); // ("1.jpg", "12.jpg", "2.jpg", "20.jpg", "4.jpg")
$second = natsort($array); // ("1.jpg", "2.jpg", "4.jpg", "12.jpg", "20.jpg")
next

mixed next(array array)

Increments the internal pointer to the element after the current element and returns the value of the element to which the internal pointer is now set. If the internal pointer already points beyond the last element in the array, the function returns false.

Be careful when iterating over an array using this function—if an array contains an empty element or an element with a key value of 0, a value equivalent to false is returned, causing the loop to end. If an array might contain empty elements or an element with a key of 0, use the each function instead of a loop with next.

nl2br

string nl2br(string string)

Returns a string created by inserting <br /> before all newline characters in string.

number_format

string number_format(double number[, int precision[, string decimal_separator,
                      string thousands_separator]])

Creates a string representation of number. If precision is given, the number is rounded to that many decimal places; the default is no decimal places, creating an integer. If decimal_separator and thousands_separator are provided, they are used as the decimal-place character and thousands separator, respectively. They default to the English locale versions ("." and ","). For example:

$number = 7123.456;
$english = number_format($number, 2); // 7,123.45
$francais = number_format($number, 2, ',', ' '); // 7 123,45
$deutsche = number_format($number, 2, ',', '.'); // 7.123,45

If rounding occurs, proper rounding is performed, which may not be what you expect (see round).

ob_end_clean

void ob_end_clean( )

Turns off output buffering and empties the current buffer without sending it to the client. See Chapter 13 for more information on using the output buffer.

ob_end_flush

void ob_end_flush( )

Sends the current output buffer to the client and stops output buffering. See Chapter 13 for more information on using the output buffer.

ob_get_contents

string ob_get_contents( )

Returns the current contents of the output buffer; if buffering has not been enabled with a previous call to ob_start( ), returns false. See Chapter 13 for more information on using the output buffer.

ob_get_length

int ob_get_length( )

Returns the length of the current output buffer, or false if output buffering isn't enabled. See Chapter 13 for more information on using the output buffer.

ob_gzhandler

string ob_gzhandler(string buffer[, int mode])

This function gzip-compresses output before it is sent to the browser. You don't call this function directly. Rather, it is used as a handler for output buffering using the ob_start( ) function. To enable gzip-compression, call ob_start( ) with this function's name:

<?php ob_start("ob_gzhandler"); ?>
ob_implicit_flush

void ob_implicit_flush([int flag])

If flag is true or unspecified, turns on output buffering with implicit flushing. When implicit flushing is enabled, the output buffer is cleared and sent to the client after any output (such as the printf( ) and echo( ) functions). See Chapter 13 for more information on using the output buffer.

ob_start

void ob_start([string callback])

Turns on output buffering, which causes all output to be accumulated in a buffer instead of being sent directly to the browser. If callback is specified, it is a function (called before sending the output buffer to the client) that can modify the data in any way; the ob_gzhandler( ) function is provided to compress the output buffer in a client-aware manner. See Chapter 13 for more information on using the output buffer.

octdec

int octdec(string octal)

Converts octal to its decimal value. Up to a 32-bit number, or 2,147,483,647 decimal (017777777777 octal), can be converted.

opendir

int opendir(string path)

Opens the directory path and returns a directory handle for the path that is suitable for use in subsequent readdir( ), rewinddir( ), and closedir( ) calls. If path is not a valid directory, if permissions do not allow the PHP process to read the directory, or if any other error occurs, false is returned.

openlog

int openlog(string identity, int options, int facility)

Opens a connection to the system logger. Each message sent to the logger with a subsequent call to syslog( ) is prepended by identity. Various options can be specified by options; OR any options you want to include. The valid options are:

 

LOG_CONS

 

If an error occurs while writing to the system log, write the error to the system console.

 

LOG_NDELAY

 

Open the system log immediately.

 

LOG_ODELAY

 

Delay opening the system log until the first message is written to it.

 

LOG_PERROR

 

Print this message to standard error in addition to writing it to the system log.

 

LOG_PID

 

Include the PID in each message.

The third parameter, facility, tells the system log what kind of program is logging to the system log. The following facilities are available:

 

LOG_AUTH

 

Security and authorization errors (deprecated; if LOG_AUTHPRIV is available, use it instead)

 

LOG_AUTHPRIV

 

Security and authorization errors

 

LOG_CRON

 

Clock daemon (cron and at) errors

 

LOG_DAEMON

 

Errors for system daemons not given their own codes

 

LOG_KERN

 

Kernel errors

 

LOG_LPR

 

Line printer subsystem errors

 

LOG_MAIL

 

Mail errors

 

LOG_NEWS

 

USENET news system errors

 

LOG_SYSLOG

 

Errors generated internally by syslogd

 

LOG_AUTHPRIV

 

Security and authorization errors

 

LOG_USER

 

Generic user-level errors

 

LOG_UUCP

 

UUCP errors

ord

int ord(string string)

Returns the ASCII value of the first character in string.

pack

string pack(string format, mixed arg1[, mixed arg2[, ... mixed argN]])

Creates a binary string containing packed versions of the given arguments according to format. Each character may be followed by a number of arguments to use in that format, or an asterisk (*), which uses all arguments to the end of the input data. If no repeater argument is specified, a single argument is used for the format character. The following characters are meaningful in the format string:

 

a

 

NUL-byte-padded string

 

A

 

Space-padded string

 

h

 

Hexadecimal string, with the low nibble first

 

H

 

Hexadecimal string, with the high nibble first

 

c

 

Signed char

 

C

 

Unsigned char

 

s

 

16-bit, machine-dependent byte-ordered signed short

 

S

 

16-bit, machine-dependent byte-ordered unsigned short

 

n

 

16-bit, big-endian byte-ordered unsigned short

 

v

 

16-bit, little-endian byte-ordered unsigned short

 

i

 

Machine-dependent size and byte-ordered signed integer

 

I

 

Machine-dependent size and byte-ordered unsigned integer

 

l

 

32-bit, machine-dependent byte-ordered signed long

 

L

 

32-bit, machine-dependent byte-ordered unsigned long

 

N

 

32-bit, big-endian byte-ordered unsigned long

 

V

 

32-bit, little-endian byte-ordered unsigned long

 

f

 

Float in machine-dependent size and representation

 

d

 

Double in machine-dependent size and representation

 

x

 

NUL-byte

 

X

 

Back up one byte

 

@

 

Fill to absolute position (given by the repeater argument) with NUL-bytes

parse_ini_file

array parse_ini_file(string filename[, bool process_sections])

Loads filename, a file in the standard PHP .ini format, and returns the values in it as an associative array. If process_sections is set and is true, a multidimensional array with values for the sections in the file is returned.

This function does not bring the values in filename into PHP—it is only meant to allow you to create configuration files for your applications in the same format as PHP's php.ini file.

parse_str

void parse_str(string string[, array variables])

Parses string as if coming from an HTTP POST request, setting variables in the local scope to the values found in the string. If variables is given, the array is set with keys and values from the string.

parse_url

array parse_url(string url)

Returns an associative array of the component parts of url. The array contains the following values:

 

fragment

 

The named anchor in the URL

 

host

 

The host

 

pass

 

The user's password

 

path

 

The requested path (which may be a directory or a file)

 

port

 

The port to use for the protocol

 

query

 

The query information

 

scheme

 

The protocol in the URL, such as "http"

 

user

 

The user given in the URL

The array will not contain values for components not specified in the URL. For example:

$url = "http://www.oreilly.net/search.php#place?name=php&type=book";
$array = parse_url($url);
print_r($array); // contains values for "scheme", "host", "path", "query",
                 // and "fragment"
passthru

void passthru(string command[, int return])

Executes command via the shell and outputs the results of the command into the page. If return is specified, it is set to the return status of the command. If you want to capture the results of the command, use exec( ).

pathinfo

array pathinfo(string path)

Returns an associative array containing information about path. The following elements are in the returned array:

 

dirname

 

The directory in which path is contained.

 

basename

 

The basename (see basename) of path, including the file's extension.

 

extension

 

The extension, if any, on the file's name. Does not include the period at the beginning of the extension.

pclose

int pclose(int handle)

Closes the pipe referenced by handle. Returns the termination code of the process that was run in the pipe.

pfsockopen

int pfsockopen(string host, int port[, int error[, string message
               [, double timeout]]])

Opens a persistent TCP or UDP connection to a remote host on a specific port. By default, TCP is used; to connect via UDP, host must begin with udp://. If specified, timeout indicates the length of time in seconds to wait before timing out.

If the connection is successful, the function returns a virtual file pointer that can be used with functions such as fgets( ) and fputs( ). If the connection fails, it returns false. If error and message are supplied, they are set to the error number and error string, respectively.

Unlike fsockopen( ), the socket opened by this function does not close automatically after completing a read or write operation on it; you must close it explicitly with a call to fsclose( ).

php_logo_guid

string php_logo_guid( )

Returns an ID that you can use to link to the PHP logo. For example:

<?php $current = basename($PHP_SELF); ?>
<img src="<?= "$current?=" . php_logo_guid( ); ?>" border="0" />
php_sapi_name

string php_sapi_name( )

Returns a string describing the server API under which PHP is running; for example, "cgi" or "apache".

php_uname

string php_uname( )

Returns a string describing the operating system under which PHP is running.

phpcredits

void phpcredits([int what])

Outputs information about PHP and its developers; the information that is displayed is based on the value of what. To use more than one option, OR the values together. The possible values of what are:

 

CREDITS_ALL (default)

 

All credits except CREDITS_SAPI.

 

CREDITS_GENERAL

 

General credits about PHP.

 

CREDITS_GROUP

 

A list of the core PHP developers.

 

CREDITS_DOCS

 

Information about the documentation team.

 

CREDITS_MODULES

 

A list of the extension modules currently loaded and the authors for each.

 

CREDITS_SAPI

 

A list of the server API modules and the authors for each.

 

CREDITS_FULLPAGE

 

Indicates that the credits should be returned as a full HTML page, rather than just a fragment of HTML code. Must be used in conjunction with one or more other options; e.g., phpcredits(CREDITS_MODULES | CREDITS_FULLPAGE).

phpinfo

void phpinfo([int what])

Outputs a whole bunch of information about the state of the current PHP environment, including loaded extensions, compilation options, version, server information, and so on. If speficied, what can limit the output to specific pieces of information; what may contain several options ORed together. The possible values of what are:

 

INFO_ALL (default)

 

All information

 

INFO_GENERAL

 

General information about PHP

 

INFO_CREDITS

 

Credits for PHP, including the authors

 

INFO_CONFIGURATION

 

Configuration and compilation options

 

INFO_MODULES

 

Currently loaded extensions

 

INFO_ENVIRONMENT

 

Information about the PHP environment

 

INFO_VARIABLES

 

A list of the current variables and their values

 

INFO_LICENSE

 

The PHP license

phpversion

string phpversion( )

Returns the version of the currently running PHP parser.

pi

double pi( )

Returns an approximate value of pi.

popen

int popen(string command, string mode)

Opens a pipe to a process executed by running command on the shell.

The parameter mode specifies the permissions to open the file with, which can only be unidirectional (that is, for reading or writing only). mode must be one of the following:

 

r

 

Open file for reading; file pointer will be at beginning of file.

 

w

 

Open file for writing. If the file exists, it will be truncated to zero length; if the file doesn't already exist, it will be created.

If any error occurs while attempting to open the pipe, false is returned. If not, the resource handle for the pipe is returned.

pos

mixed pos(array array)

This function is an alias for current( ).

pow

mixed pow(double base, double exponent)

Returns base raised to the exponent power. When possible, the return value is an integer; if not, it is a double.

prev

mixed prev(array array)

Moves the internal pointer to the element before its current location and returns the value of the element to which the internal pointer is now set. If the internal pointer is already set to the first element in the array, returns false. Be careful when iterating over an array using this function—if an array has an empty element or an element with a key value of 0, a value equivalent to false is returned, causing the loop to end. If an array might contain empty elements or an element with a key of 0, use the each( ) function instead of a loop with prev( ).

print

void print(string string)

Outputs string. Similar to echo, except that it takes a single argument.

print_r

bool print_r(mixed value)

Outputs value in a human-readable manner. If value is a string, integer, or double, the value itself is output; if it is an array, the keys and elements are shown; and if it is an object, the keys and values for the object are displayed. This function returns true.

printf

int printf(string format[, mixed arg1 ...])

Outputs a string created by using format and the given arguments. The arguments are placed into the string in various places denoted by special markers in the format string.

Each marker starts with a percent sign (%) and consists of the following elements, in order. Except for the type specifier, the specifiers are all optional. To include a percent sign in the string, use %%.

putenv

void putenv(string setting)

Sets an environment variable using setting, which is typically in the form name = value.

quoted_printable_decode

string quoted_printable_decode(string string)

Decodes string, which is data encoded using the quoted printable encoding, and returns the resulting string.

quotemeta

string quotemeta(string string)

Escapes instances of certain characters in string by appending a backslash (\) to them and returns the resulting string. The following characters are escaped: period (.), backslash (\), plus sign (+), asterisk (*), question mark (?), brackets ([ and ]), caret (^), parentheses (( and )), and dollar sign ($).



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