• simple grammer


    <?php
    echo strlen("Hello world!"); // outputs 12
    ?>

    <?php
    echo str_word_count("Hello world!"); // outputs 2
    ?>

    <?php
    echo strrev("Hello world!"); // outputs !dlrow olleH
    ?>

    <?php
    echo strpos("Hello world!", "world"); // outputs 6.  If no match is found, it will return FALSE.
    ?>

    <?php
    echo str_replace("world", "Dolly", "Hello world!"); // outputs Hello Dolly!
    ?>

    <?php
    define("GREETING", "Welcome to W3Schools.com!");  // syntax: define(namevaluecase-insensitive)
    echo GREETING;
    ?>

    operation

    ===  $x === $y return true if $x is equal to $y, and they are of the same type

    <>    $x <> $y    return true if $x is not equal to $y

    !==   $x !== $y   return true if $x is not equal to $y, or they are not of the same

    if (condition) {
        code to be executed if this condition is true;
    } elseif (condition) {
        code to be executed if this condition is true;
    } else {
        code to be executed if all conditions are false;
    }

    e.g:

    <?php
    $t = date("H");

    if ($t < "10") {
        echo "Have a good morning!";
    } elseif ($t < "20") {
        echo "Have a good day!";
    } else {
        echo "Have a good night!";
    }
    ?>

    foreach ($array as $value) {
        code to be executed;
    }

    e.g:

    <?php 
    $colors = array("red", "green", "blue", "yellow"); 

    foreach ($colors as $value) {
        echo "$value <br>";
    }
    ?>

    <?php
    function setHeight($minheight = 50) {
        echo "The height is : $minheight <br>";
    }

    setHeight(350);
    setHeight(); // will use the default value of 50
    setHeight(135);
    setHeight(80);
    ?>

    <?php
    $cars = array("Volvo", "BMW", "Toyota");
    echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";
    ?>

    <?php
    $cars = array("Volvo", "BMW", "Toyota");
    echo count($cars);  //output 3
    ?>

    PHP Associative Arrays:associative arrays are arrays that use named keys that you assigin to them

    <?php

    $age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
    echo "Peter is " . $age['Peter'] . " years old.";
    ?>

    <?php
    $age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

    foreach($age as $x => $x_value) {
        echo "Key=" . $x . ", Value=" . $x_value;
        echo "<br>";
    }
    ?>

    Sort Funcitions For Arrays 

    sort() -- sort arrays in ascending order

    rsort() -- sort arrays in descending order

    asort() -- sort associative arrays in ascending order, according to the value

    ksort() -- sort associative arrays in ascending order, according to the key

    arsort() -- sort associative arrays in descending order, according to the value

    krsort() -- sort associative arrays in descending order, according to the key

    Superglobals: PHP Global Variables

    Several predefined variables in PHP are "superglobals", which means that they are always accessible, regardless of scope - and you can access them from any function, class or file without having to do anything special.

    The PHO superglobal variables are: 

    $GLOBALS  $_SERVER  $_REQUEST  $_POST  $_GET  $_FILES  $_ENV  $_COOKIE  $_SESSION

    <?php 
    echo $_SERVER['PHP_SELF'];  // Returns the filename of the currency executing script
    echo "<br>";
    echo $_SERVER['SERVER_NAME'];  // Returns the IP address of the host server
    echo "<br>";
    echo $_SERVER['HTTP_HOST'];  // Returns the host header from the current request
    echo "<br>";
    echo $_SERVER['HTTP_REFERER'];  // Returns the complete URL of the current page
    echo "<br>";
    echo $_SERVER['HTTP_USER_AGENT'];
    echo "<br>";
    echo $_SERVER['SCRIPT_NAME'];  // Return the URI of the current page
    ?>

    $_SERVER['GATEWAY_INTERFACE']  returns the version of the Common Gateway Interface the server is using

    $_SERVER['SERVER_ADDR']  returns the IP address of the host server

    $_SERVER['SERVER_SOFTWARE'] returns the server identification string

    $_SERVER['SERVER_PROTOCOL'] returns the name and reversion of the information protocol

    $_SERVER['REQUEST_METHOD'] return the request method used to access the page

    $_SERVER['QUERY_STRING'] return the query string if the page is accessed via a query string

    $_SERVER['HTTP_ACCEPT'] return the Accept header from the current request

    $_SERVER['HTTPP_ACCEPT_CHARSET'] return the Accept_Charset header from the current request

    $_SERVER['HTTP_HOST'] return the host header from the current request

    $_SERVER['HTTP_REFERER'] return the complete URL of the current page

    $_SERVER['HTTPS'] is the script queried through a secure HTTP protocol

    $_SERVER['REMOTE_ADDR'] return the IP address from where the user is viewing the current page

    $_SERVER['REMOTE_HOST'] return the host name from where the user is viewing the current page

    $_SERVER['REMOTE_PORT'] return the port being used on the user's machine to communicate with the web server

    $_SERVER['SCRIPT_FILENAME'] return the absolute pathname of the currently executing script

    $_SERVER['SERVER_ADMIN'] return the value given to the SERVER_ADMIN directive in the web server configuration file

    $_SERVER['SERVER_PORT'] return the port on the server machine being used by the web server for communication

    $_SERVER['SERVER_SIGNATURE'] return the server version and virtual host name which are used by the web server for communication

    $_SERVER['PATH_TRANSLATED'] return the file system based path to the current script

    $_SERVER['SCRIPT_NAME'] return the path of current script

    $_SERVER['SCRIPT_URI'] return the URI of the current page

    PHP $_REQUEST is used to collect data after submitting an HTML form 

    <html>
    <body>

    <form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
      Name: <input type="text" name="fname">
      <input type="submit">
    </form>

    <?php
    if ($_SERVER["REQUEST_METHOD"] == "POST") {
        // collect value of input field
        $name = $_REQUEST['fname'];
        if (empty($name)) {
            echo "Name is empty";
        } else {
            echo $name;
        }
    }
    ?>

    </body>
    </html>

    PHP $_POST is used to collect form data after submitting an HTML form with method = "post",$_POST is also widely used to pass variables

    <html>
    <body>

    <form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
      Name: <input type="text" name="fname">
      <input type="submit">
    </form>

    <?php
    if ($_SERVER["REQUEST_METHOD"] == "POST") {
        // collect value of input field
        $name = $_POST['fname'];
        if (empty($name)) {
            echo "Name is empty";
        } else {
            echo $name;
        }
    }
    ?>

    </body>
    </html>

    PHP $_GET is used to collect form data after submitting an HTML form with method="get".$_GET can also collect data sent in the URI

    <html>
    <body>

    <?php 
    echo "Study " . $_GET['subject'] . " at " . $_GET['web'];
    ?>

    </body>
    </html>

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  • 原文地址:https://www.cnblogs.com/forerver-elf/p/5191147.html
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