PHP character function encyclopedia page 1/2_PHP tutorial

AddSlashes: Add slashes to strings.
bin2hex: Convert binary to hexadecimal.
Chop: Remove consecutive blank spaces.
Chr: Returns the ordinal value of the character.
chunk_split: Divide the string into small segments.
convert_cyr_string: Convert ancient Cyrillic strings into other strings.
crypt: Encrypt the string using DES encoding.
echo: Output string.
explode: Split the string.
flush: Clear the output buffer.
get_meta_tags: Extract all meta-tagged data from the file.
htmlspecialchars: Convert special characters into HTML format.
htmlentities: Convert all characters into HTML strings.
implode: Convert array into string.
join: Convert array into string.
ltrim: Remove continuous whitespace.
md5: Calculate the MD5 hash of a string.
nl2br: Convert newline characters into
.
Ord: Returns the ordinal value of the character.
parse_str: Parse query string into variables.
print: Output string.
printf: Output formatted string.
quoted_printable_decode: Convert qp encoded string into 8-bit string.
QuoteMeta: Add quote symbol.
rawurldecode: Revert from URL special format string to ordinary string.
rawurlencode: Encode string into URL-specific format.
setlocale: Configure localization information.
similar_text: Calculate string similarity.
soundex: Calculate the pronunciation value of the string
sprintf: Format the string.
strchr: Find the first character that appears.
strcmp: String comparison.
strcspn: The length of different strings.
strip_tags: Remove HTML and PHP tags.
StripSlashes: Remove backslash characters.
strlen: Get the length of the string.
strrpos: Find the last occurrence of a character in a string.
strpos: Find the first occurrence of a character in a string.
strrchr: Get the string starting from the last occurrence of a character.
strrev: Reverse the string.
strspn: Find the number of times a string falls within the mask of another string.
strstr: Returns the string from the beginning to the end of a string in the string.
strtok: Cut the string.
strtolower: Convert all strings to lowercase.
strtoupper: Convert all strings to uppercase.
str_replace: String replacement.
strtr: Convert certain characters.
substr: Get part of the string.
trim: Trim the spaces at the beginning and end of the string.
ucfirst: Change the first character of the string to uppercase.
ucwords: Capitalize the first letter of each word in the string.


Return value: String
Function type: Data processing
Content description: This function uses the string that needs to be processed by the database, and adds slashes to the quotation marks. Database queries can run smoothly. The characters that will be changed include single quotes ('), double quotes ("), backslash () and the null character NUL (the null byte).
Reference: stripslashes() htmlspecialchars() quotemeta()


Return value: String
Function type: Data processing
Content description: This function converts a binary string into a hexadecimal string
Usage example
Supplement:
josh@superfork.com (22-Jun-1999) wrote a function that can convert hexadecimal to binary.
function hex2bin($data) {
$len = strlen($data);
for($i=0;$i<$len;$i+=2) {
$newdata .= pack("C",hexdec(substr($ string,$i,2)));
}
return $newdata;
}
?>


Return value: String
Function type : Data processing
Content description: This function clears consecutive blanks in the string
Example of use
$trimmed = Chop($line);
?>
>Reference: trim()


Return value: String
Function type: Data processing
Content description: This function converts the ordinal number of characters into ASCII characters. This function is the same as ord. ()
Usage example
$str .= chr(27);
$str = sprintf("The end character of the string is: %c", 27) ;
?>
Reference: ord() sprintf()


Return value: String
Function type: Data processing
Content description: This function converts characters into small segments for use by other functions, for example, base64_encode.The default is that the parameter chunklen (76 characters) inserts end ("rn") every 76 characters. Returns a new string without modifying the original string.
Usage example
Format string $data into MIME BASE64 format
$new_string = chunk_split(base64_encode($data));
?>
Reference: ereg_replace()


Return value: String
Function type: Data processing
Content description: This function converts ancient Cyrillic strings into other strings. The two parameters from and to are characters, and their meanings are as follows:
k - koi8-r
w - windows-1251
i - iso8859-5
a - x-cp866
d - x-cp866
m - x-mac-cyrillic


Syntax: string crypt(string str, string [salt]);
Return value: String
Function type : Encoding processing
Content description: This function encrypts a string using UNIX's standard encryption DES module. This is a one-way encryption function and cannot be decrypted. To compare strings, place the first two characters of the encrypted string in the salt parameter, and then compare the encrypted strings.
For more detailed information, please refer to crypt in UNIX Manual (man).
In some newer UNIX versions, in addition to DES, other encryption modules are also provided, such as MD5. Some systems even use MD5 instead of DES. There are some changes in the salt parameter, depending on the length of the string passed to the salt parameter:
CRYPT_STD_DES - Standard DES encoding, enter a 2-character salt.
CRYPT_EXT_DES - Extended DES encoding, enter a 9-character salt.
CRYPT_MD5 - MD5 encoding, enter 12 characters plus $1$ salt.
CRYPT_BLOWFISH - Extended DES encoding, input 16 characters plus $2$ salt.
In addition, if the salt parameter is not used, the program will be generated automatically.


Return value: None
Function type: PHP system function
Content description: This function outputs a string. Since it is not a real function, it has no return value.
Usage example
echo "Hello World";
?>
Reference: print() printf() flush()


Return value: Array
Function type: Data processing
Content description: This function cuts the string according to the specified string or character separator. Return the cut string into an array variable.
Example of use
$pizza = "First piece Second piece Third piece Fourth piece Fifth piece Sixth piece";
$pieces = explode(" ", $ pizza);
?>
Reference: implode()


Return value: None
Function type: Data processing
Content description: This function has no input and nothing output. Send the data in the output buffer and clear it.


Syntax: array get_meta_tags(string filename, int [use_include_path]);
Return value: Array
Function type: Data processing
Content description: This function will All data marked with are taken out and placed in array variables and returned. For example






This function finds the meta tag, the string of the name attribute is the array index, and content The attribute string is the content of the array. Please note that this function is a PHP native function and cannot directly handle the Macintosh file format on UNIX series platforms because the newline characters are different. blake@mediaone.net pointed out (07-Jun-1999) that the parameter filename can also be a URL, and the function will extract the file meta tag of the remote server. When the function is processing, it ends when it encounters the mark. If the mark is placed after , it will not be processed.


Syntax: string htmlspecialchars(string string);
Return value: String
Function type: Data processing
Content description: This function converts special characters into HTML characters String format ( &....; ). The most commonly used occasion may be the message board for processing customer messages.
& (and) is converted to &
" (double quotes) is converted to "
< (less than) is converted to <
> (greater than) is converted to >
This function Only the above special characters are converted, not all of them are converted into ASCII conversion specified by HTML.
Usage Example
This is an example provided by aulbach@unter.franken.de (27-Jan-1999)