PHP light speed tutorial
Date: | Source: redice's Blog | author: redice | 182 onlookers | 0 people applaud! // By redice 2010.07.29
// Redice@163.com
Based on your own learning experience and project development experience, I have summarized the most important PHP language knowledge points. It can be used as a PHP Quick Start tutorial.
1. client script and server script
Client: VBscript (highly dependent on IE, discard), Javascript
Server: ASP, PHP, Perl
JSP (server, non-script)
Python (available server, non-script)
2. key points/sequence of learning a language
Functions, features, syntax, variables, operators, process control, functions, and data structures
3. key points for learning the server language
Data input and output, database operations, session and cookie usage
4. PHP functions
Supports data processing in combination with a variety of server software (Apache, iis isapi/FastCGI, Nginx, etc.)
5. PHP features
Cross-platform, built-in function libraries are rich (much less written), simple syntax, and many references
6. PHP syntax
// This is the comment line. the comment line starts //
Phpinfo (); // The statement ends;
?>
7. PHP variables
Loose type, automatic declaration, forced conversion
PHP variables start with $ (a very affordable language starting with money)
$ Txt = "Hello World! "; // The string is enclosed by" ", escape ",\
$ Number = 16;
?>
Loose language: VB, VBscript, ASP, PHP, Python
Strong language: C (C ++), JSP
8 PHP operators
Arithmetic operations: +,-, *,/, % (remainder), ++ (auto Increment 1), -- (auto Increment 1)
Value assignment: =, + =,-=, * =,/=,. =, % =
Comparison operator: =, = ,! =,>, <, >=, <=
Logical operators: &, | ,!
Other operators:. (string join)
$ I = 10;
$ I + = 1;
Echo $ I; // echo data output function, you can also use print
Echo ++ $ I ;//?
Echo $ I ++ ;//?
?>
* Equal sign and third sign
= Only compare whether the values are equal, type conversion is performed on both sides
=== Whether the comparison value and type are the same, no type conversion is performed, and the type and value are the same to true
For example:
$ A = "2"; // string type 2
$ B = 2; // numeric type 2
$ A = $ B, yes, both are 2
$ A ===$ B, which is incorrect, because $ a is numeric and $ B is numeric. although the value is the same, the type is different.
9 PHP process control
Sequential statements
Branch statement: if else, Switch
// If else statement
If (condition)
Code to be executed if condition is true;
Elseif (condition)
Code to be executed if condition is true;
Else
Code to be executed if condition is false;
// Switch statement
Switch (expression)
{
Case label1:
Code to be executed if expression = label1;
Break;
Case label2:
Code to be executed if expression = label2;
Break;
Default:
Code to be executed
If expression is different
From both label1 and label2;
}
Loop statement: while, for, foreach
// While loop
While (condition)
Code to be executed;
// For loop
For (initialization; condition; increment)
{
Code to be executed;
}
// Foreach loop, traversing the array
Foreach (array as value)
{
Code to be executed;
}
// Foreach loop example
$ Arr = array ("one", "two", "three ");
Foreach ($ arr as $ value)
{
Echo "Value:". $ value ."
";
}
?>
* End PHP program execution:
Exit ($ str); // end PHP execution and output $ str
Die (); // Only end PHP execution
10 PHP functions
Built-in functions:
Http://php.chinaunix.net/manual/en/
(1) data output: echo, print, print_r (output array)
(2) string operations:
// Returns the length of $ string.
Int strlen (string $ string)
// Delete spaces or other characters at both ends of $ str
String trim (string $ str [, string $ charlist])
$ Str = "xiao ping ni hao! ";
Echo trim ($ str );
Echo"
";
Echo trim ($ str, "x! ")
?>
// Case-insensitive string
String strtolower (string $ str)
String strtoupper (string $ string)
// Search for strings
Int strpos (string $ haystack, mixed $ needle [, int $ offset = 0])
Return value: return the position of the substring. If no substring is found, false is returned.
Note:
If the substring $ needle appears at the beginning of $ haystack, 0 is returned.
Therefore, to determine whether to find the string, use = instead of =.
$ Str = "redicecn.com ";
// The following is an incorrect judgment
If (strpos ($ str, "redice") = false)
{
Echo "no substring found! ";
}
Else
{
Echo "found the substring! ";
}
?>
// String truncation
String substr (string $ string, int $ start [, int $ length])
// String replacement
String str_replace (mixed $ search, mixed $ replace, mixed $ subject)
String str_ireplace (mixed $ search, mixed $ replace, mixed $ subject) // case insensitive
(3) date and time:
// The time () function returns the Unix timestamp of the current time.
Time (void)
// Date () function format a local time/date
// The default value is Greenwich mean time zone.
Date (format, timestamp)
// Set it to East 8
Date_default_timezone_set ('etc/GMT-8 ');
Echo date ("Y-m-d H: I: s", time ());
?>
Custom functions:
$ Sitename = "E-engineering community ";
Function welcom ($ user)
{
Global $ sitename; // Reference global variables
// Return value
Return $ user. ", welcome to". $ sitename ."! ";
}
// Function call
Echo welcom ("redice ");
?>
11. PHP Data structure
Array
// Numeric array definition
(1) automatically allocate keys
$ Names = array ("Sister Furong", "Sister Feng", "Sharp Brother ");
(2) manually allocate keys
$ Names [0] = "Sister Furong ";
$ Names [1] = "Fengjie ";
$ Names [2] = "sharp brother ";
// Define the associated array
$ Ages = array ("Sister Furong" => 32, "sister Fengjie" => 29, "Sharp Brother" => 42 );
You can also
$ Ages ["Sister Furong"] = 32;
$ Ages ["Fengjie"] = 29;
$ Ages ["Rhinoceros"] = 42;
// Multi-dimensional array
$ Students = array
(
& Quot; 0911120688 & quot; = & gt; array
(
"Name" => "Qi Peng ",
"Age" => 24,
"Gender" => "male"
),
& Quot; 0911120699 & quot; = & gt; array
(
"Name" => "song Yuwei ",
"Age" => 22,
"Gender" => "female"
),
& Quot; 0911120670 & quot; = & gt; array
(
"Name" => "Chen Sufang ",
"Age" => 22,
"Gender" => "female"
)
);
12. PHP input (obtain client input)
(1) $ _ GET variable
The $ _ GET variable is an array with the variable name and value sent by the http get method.
(2) $ _ POST variable
The $ _ POST variable is an array with the variable name and value sent by the http post method.
(3) $ _ REQUEST variable
The $ _ REQUEST variable in PHP contains $ _ GET, $ _ POST, and $ _ COOKIE content.
13 SESSION and COOKIE usage
(1) SESSION
Stored on the server, the server is determined by the SESSIONID in the COOKIE, which is often used for identity authentication.
Run session_start () to start a SESSION,
Because session_start () needs to modify the COOKIE header (save SESSIONID) of the HTTP response message ),
Therefore, session_start () must be called before the HTTP response body is output.
// Create a session
Session_start ();
$ _ SESSION ['user'] = "redice ";
?>
// Read the session
Session_start ();
Echo $ _ SESSION ['user'];
?>
Delete SESSION
Unset ($ _ SESSION ['user']);
?>
Or
Session_destroy (); // All sessions will be deleted.
?>
(2) COOKIE
Stored on the client and sent together with the request message to the server,
It is often used to store user-defined settings, browsing records, and other security-independent data.
* Cookies are stored on the client and can be modified by users. Therefore, sensitive data cannot be stored.
// Create a cookie
Setcookie (name, value, expire );
Setcookie () also needs to modify the HTTP response header, so it needs to be called before outputting any body
Setcookie ("user", "redice", time () + 3600 );
?>
// Read cookie
Echo $ _ COOKIE ["user"];
?>
// Delete the cookie
// Set to expire immediately, and the client (browser) will be automatically deleted
Setcookie ("user", "", time ()-3600 );
?>
14 database operations
Procedure:
Connect to database-> Select database-> set the character set used
-> Operation data (query, update, delete, and insert)-> Close the database
$ Conn = 0;
$ Conn = mysql_connect ("localhost", "root", "redice2009 ");
If (! $ Conn)
{
Die ("cannot open the database connection, error:". mysql_error ());
}
// Select a database
Mysql_select_db ("thymall", $ conn );
// Set the character set of mysql output data
Mysql_query ("set names 'gbk '");
$ SQL = "select * from thym_goods LIMIT 5 ";
// Execute the query
$ Result = mysql_query ($ SQL, $ conn );
// Traverse the query results
While ($ result & $ row = mysql_fetch_array ($ result ))
{
}
// Close the database
Mysql_close ($ conn );
?>
15 others
Good program style: indent, comment
Selection principles of development tools: code keywords highlighted, automatically completed
