Syntax string chopstring str Description The chop function returns the str parameter without any trailing whitespace.. chr Syntax string chrint ascii Description The chr function r
Trang 1Syntax
string chop(string str)
Description
The chop() function returns the str parameter without any trailing whitespace
Whitespace includes "\\ n", "\\ r", "\\ t", "\\ v", "\\ 0", and a plain space
chr()
Syntax
string chr(int ascii)
Description
The chr() function returns a one-character string that corresponds to the ASCII code specified by the parameter
echo chr(65);//displays A
chunk_split()
Syntax
string chunk_split(string string, int [chunklen] , string [end])
Description
The chunk_split() function, which was added in PHP 3.0.6 and PHP 4.0, returns
string broken up at every chunklen characters by the string end The optional
parameter chunklen defaults to 76, and end defaults to ("\\ r\\ n") In other words, the default behavior is to take a long string and break it into multiple lines of length 76 This can be useful for converting base64-endcoded output to match RFC
2045 semantics Base64 encoding is used to preserve binary data when transferring
it via electronic mail
convert_cyr_string()
Trang 2Syntax
string convert_cyr_string(string str, string from, string to);
Description
The convert_cyr_string() function, which was added in PHP 3.0.6 and PHP 4.0, returns str converted from one Cyrillic character set to another The from and to
parameters are single characters that represent Cyrillic character sets The str is the
character set to which it should be converted The supported types of Cyrillic character sets are
k—koi8-r
w—Windows-1251
i—ISO8859-5
a—x-cp866
d—x-cp866
m—x-mac-cyrillic
count_chars()
Syntax
mixed count_chars(string string, [mode]);
Description
The count_chars() function, which was added in PHP 4.0, counts the number of occurrences of each byte value (0–255) in string and returns the information in a
format determined by mode If mode is not specified, it defaults to 0 The options for
mode include:
0—An array with the key representing the byte value and the value
representing the frequency of each byte
1—An array similar to 0 but only non-zero frequency byte values are
listed
2—An array similar to 0 but only zero frequency byte values are listed
Trang 33—A string is returned containing only the byte values that are used
4—A string is returned containing only the byte values that are not
used
crc32()
Syntax
int crc32(string str)
Description
The crc32() function, which was added in PHP 4.0.1, calculates the crc32 polynomial
of the string This is typically used to validate data that has been transmitted
crypt()
Syntax
string crypt(string str, string [salt] )
Description
The crypt() function encrypts str using the standard UNIX DES encryption method
The salt is an optional two-character parameter on which the encryption is based If
salt is not provided, PHP will randomly generate one For some operating systems,
an MD5-based encryption algorithm replaces the standard DES encryption The encryption type is specified by the salt parameter During installation of PHP, it is
determined which encryption functions are in use on the system If salt is not
specified, PHP will auto-generate a salt based on the default encryption type for the
system Either the standard 2-character DES salt or a random MD5-compatible salt is generated You can determine which encryption method is in use by examining the constant CRYPT_SALT_LENGTH
The output will contain the salt as the first two numbers when using the standard
DES encryption crypt() function
On systems where multiple encryption types are supported, the crypt() function accepts either 0 or 1, depending on whether the given type is available:
CRYPT_STD_DES—Standard DES encryption with a 2-character salt
CRYPT_EXT_DES—Extended DES encryption with a 9-char salt
Trang 4CRYPT_MD5—MD5 encryption with a 12-char salt where the first
characters of the result are $1$
CRYPT_BLOWFISH—Extended DES encryption with a 16-char salt where
the first characters of the result are $2$
Note that crypt() is a one-direction algorithm The original str cannot be
determined from the resulting string
echo()
Syntax
echo(string arg1, string [argn]…)
Description
The echo() language construct outputs all the given parameters to the page Parentheses are optional with one argument and should not be used with multiple arguments
echo "Hello World!";// display Hello World message to user
explode()
Syntax
array explode(string separator, string string)
Description
The explode() function returns an array of strings where each element is from the
string parameter, which is broken out by the separator field
$array1 = explode(",","1,2,3");//$array1 = (1,2,3)
flush()
Syntax
Trang 5void flush(void)
Description
The flush() function tries to force the current output to be returned to the user The actual results depend on the method PHP is using for delivery
get_html_translation_table
Syntax
string get_html_translation_table(int table)
Description
The get_html_translation_table() function, which was added in PHP 4.0b4, returns the translation table that is used internally for htmlspecialchars() and
htmlentities() You should use HTML_ENTITIES OR HTML_SPECIALCHARS to specify which table you want
get_meta_tags()
Syntax
array get_meta_tags(string filename, int [use_include_path] )
Description
The get_meta_tags() function, which was added in PHP 3.04 and PHP 4.0, opens a file specified by filename and parses it looking for any <meta> HTML tags In the array that is returned, the name property of each meta tag becomes the key and the contents of each meta tag becomes the value If any special characters exist in the value of the name property, they are substituted with '_', and the rest of the value
is converted to lowercase Specifying use_include_path as 1 asks PHP to look for the file along the standard include path
htmlentities()
Syntax
string htmlentities(string string)