PHP Advanced 1

1.php Time function

The UNIX timestamp (called: timestamp) is an important concept in PHP for time and date, which represents the sum of the seconds from January 1, 1970 to the current time. PHP provides a built-in function time () to get the timestamp of the current time of the server.

(1) Date ()

PHP has a date () function built into it to get the current day and time. Format: Date (timestamp format, specified timestamp "optional")

Var_dump (Date ("y-m-d h:i:s"));//2016-11-16 21:10:13

Var_dump (Date ("y-m-d h:i:s"));//16-11-16 09:10:13

Var_dump (Date ("Y-m-d h:i:s", 1472903021));//returns the specified time

Var_dump (Date ("Z w"));//321 4

Microtime () function:

Returns the current microsecond and timestamp (returns a floating-point number if the given argument is true)

Var_dump (Microtime ()); 0.68103500 1479302563

Var_dump (Microtime (true)); 1479302563.6811

GETDATE () function:

Gets the current time or the text time of the specified timestamp (array form)

Thus, the equivalent can be obtained by the month and day respectively.

Date_default_timezone_set (' PRC ');Var_dump(Date_default_timezone_get ());Var_dump( Time());//int 1479367657Var_dump(Date("y-m-d h:s:d"));//2016-11-17 15:37:17Var_dump(Date("Y-m-d h:s:d", 1429366997));//2015-04-18 22:17:18Var_dump(Date("W-z"));//4-321 weeks Four This is 321 days of the yearVar_dump(Strtotime("2011-11-11"));//1320940800Var_dump(Strtotime("2011-11-11 00:00:11"));//1320940811Var_dump(Microtime());//0.39642800 1479367657Var_dump(Microtime(true));//1479367657.3964Var_dump(getdate());//ArrayVar_dump(getdate() [' Month ']);//November

2.php Math functions:

Ceil (): function rounded up to the nearest integer, return float type

Floor (): The function rounds down to the nearest integer, returning float type

Max (): function returns maximum value

MIN (): function returns the minimum value

Round (): Rounding of floating-point numbers (type float after conversion)

Mt_rand (Min, max): Returns a random integer between Min and Max

Pow (x, y): Calculates the quadratic value and returns the Y-order of X

PI (): Returns the value of pi

3. String manipulation:

If we use variables in double quotes, we can use {} to keep the variables.

$str 1 = "I am a string";

echo "abcde{$str 1}12345";

When we display special symbols in a string, we can use the escape character output.

echo "nihao\\n all Good";

Output: nihao\n Hello, everyone.

(1) String manipulation:

Trim ("Bokanwensi"): Returns a string that removes the whitespace from the string;

LTrim ("Bokanwensi"): Returns a string that deletes the left space of the string

RTrim ("Bokanwensi"): Returns a string that removes whitespace to the right of the string;

Strlen ("Bo see Evans"); A function that obtains the length of a string;

Mb_strlen ("Bo see Evans", "Utf-8"); A function that gets the length of the string, optionally encoding the format

Strtolower (): Convert all strings to lowercase

Strtoupper (): Convert string to uppercase string

Ucfirst (): Change the first letter of the string to uppercase

Ucwords (): Change the first letter of each word in a string to uppercase

Explode (".", "www.baidu.com"): Splits a string into an array according to rules and returns a new array substr (string, int start, int [length ]): Returns the truncated string, and the countdown is truncated if start is negative

Mb_substr (): Return intercept string, third parameter can modify encoding format (utf-8,gbk,gb2312)

Note: The system does not support MB_SUBSTR () in the php.ini to find Mbstring.dll; Extension=php_mbstring.dll to remove the previous;

STRCHR (data source, specified character): Starts at the beginning of the specified character, and then returns the Intercept character.

STRRCHR (data source, specified character): Starts at the end of the specified character, and returns the Intercept character.

Str_replace (parameter 1, parameter 2, Parameter 3): Parameter 1 is the replacement target, parameter 2 is the replacement content, parameter 3 is the query data source str_ireplace (parameter 1, parameter 2, Parameter 3): and Str_replace Consistent but case insensitive

MD5 (): Returns the encrypted string (irreversible encryption);

UrlEncode (): The principle of encode the URL is to first convert Chinese characters to 16, and then precede each character with an identifier%

UrlDecode (): Decrypts a URL to decode an encoded URL string by converting a hexadecimal string to a Chinese character

$str 1= ' abc ';Echo"I am a painter$str 1";//I'm a painter, abc .Echo"I am a painter$str 1 Painting Skills";//error, and then show ' I'm a painter 'Echo"I am a painter {$str 1} Strong ability ";//I'm a painter, ABC is strong .$str 2= ' Hsshidoubi ';Var_dump(Trim($str 2));//String TenVar_dump(LTrim($str 2));//stringVar_dump(RTrim($str 2));//stringVar_dump(strlen($str 2));//int$STR 3= ' Bo See Evans 12 ';Var_dump(strlen($STR 3));//intVar_dump(Mb_strlen ($STR 3, ' Utf-8 '));//int 6

$str 1= ' 123jizhimingjizhim456 ';Var_dump(STRCHR($str 1, ' m '));//mingm456Var_dump(STRRCHR($str 1, ' m '));//m456Var_dump(Str_replace(' Jizhi ', ' Lihai ',$str 1));Var_dump(Str_ireplace(' Jizhi ', ' Lihai ',$str 1));$pass= ' Hssdb ';Var_dump(MD5($pass));Var_dump(MD5(MD5($pass.‘ DB '));//Stitching a characterfunctionFnMD5 ($str){    return MD5(MD5($str.‘ Hs));}Var_dump(FnMD5 (' 12345 '));

$str= "Big Tiger egg Babbling"; Var_dump (Mb_substr ($str, 0,6)); // Big Tiger Var_dump (Mb_substr ($str, 0,5)); // garbled Var_dump (Mb_substr ($str, 0,6, ' utf-8 ')); // big tiger eggs are babbling

4. Uploading Files

Super global variable $_files

$_files-Store all kinds of information related to uploading files

$_files["File" ["Name"]-the name of the file being uploaded

$_files["File" ["type"]-the type of file being uploaded

$_files["File" ["Size"]-the size of the uploaded file, measured in bytes

$_files["File" ["Tmp_name"]-the temporary copy name of the uploaded file

$_files["File" ["Error"]-error code resulting from uploading a file 0 1 2 3 4

File_exists () function

The file_exists () function checks whether a file or directory exists

Returns true if the specified file or directory exists, otherwise false

File_exists (path) path Specifies the paths to check

Example: File_exists ("upload/". $_files["File" ["Name"])

Move_uploaded_file () function

Move_uploaded_file () function

Move the uploaded file to a new location returns true if successful, otherwise false

Move_uploaded_file (file, Newloc)

file specifies the files to be moved

Newloc new location of the required documents

Example: Move_uploaded_file ($_files["file"] ["Tmp_name"], "upload/". $_files["File" ["name"]);

Other settings

The enctype attribute of the <form> tag specifies what type of content to use when submitting a form.

Use "Multipart/form-data" when the form requires binary data, such as the contents of a file.

The type of the IE recognition jpg file must be pjpeg, and Firefox must be a jpeg.

<?PHPVar_dump($_files);if(!Empty($_files)) {    if((($_files[' File '] [' type ']== ' image/jpeg ') | | ($_files[' File '] [' type ']== ' image/png ') | | ($_files[' File '] [' type ']== ' image/gif ') | | ($_files[' File '] [' type ']== ' Image/pjpeg ')) && ($_files[' File '] [' Size ']<=102400)) {        if($_files[' File '] [' Error ']=0) {            if(file_exists("upload/".$_files["File"] ["Name"])){                Echo $_files["File"] ["Name"]. " File already exists "; }Else{                Move_uploaded_file($_files[' File '] [' Tmp_name '], "upload/".$_files[' File '] [' Name ']); }        }Else{            Echo"Error number is:".$_files[' File '] [' Error ']; }    }Else{        Echo $_files[' File '] [' name ']. " Error File "; }}? ><! DOCTYPE html>

PHP Advanced 1