Complete collection of PHP character functions_PHP tutorial

AddSlashes: Add slashes to the string.

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 the data of all meta tags in the file.

　htmlspecialchars: Convert special characters into HTML format.

　htmlentities: Convert all characters into HTML strings.

Implode: Convert an array into a string.

　Join: Convert array into string.

　ltrim: Remove continuous whitespace.

md5: Calculate the MD5 hash of a string.

nl2br: Convert newline characters to
.

Ord: Returns the ordinal value of the character.

Parse_str: Parse the query string into variables.

print: Output a string.

printf: Output formatted string.

　quoted_printable_decode: Convert qp encoded string into 8-bit string.

QuoteMeta: Add quote symbols.

Rawurldecode: Restore URL-specific format string to normal string.

rawurlencode: Encode the string into a URL-specific format.

Setlocale: Configure localization information.

Similar_text: Calculate string similarity.

Soundex: Calculate the pronunciation value of a string

　sprintf: Format 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 the string to all uppercase letters.

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 adds slashes to the quotation marks of the string that needs to be processed by the database so that the database query can operate smoothly. The characters that will be modified 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 examples

Supplement:

　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 the continuous blanks in the string.

Usage examples

　$trimmed = Chop($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 in contrast to ord().

Usage examples

　$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 turns characters into small segments for use by other functions. For example, base64_encode. Defaults to parameter chunklen (76 characters) which inserts end ("rn") every 76 characters. Returns a new string without modifying the original string.

　Usage examples

Format the 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 the UNIX 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's not a real function, it has no return value.

　Usage examples

echo "Hello World";