PHP Basic Syntax Example summary _php skill

The basic syntax of PHP is described in the example. Share to everyone for your reference, specific as follows:

demo1.php

<?php
  //echo represents the output to the browser, ECHO is actually a function
  //double quotation mark is a string of
  Echo ' read who asked you to chant, water fell fragrance floating. ';
* * * * * * * * * * * * * *
  #这也是一种注释
?>
. "?>
<script language=" php ">
  echo" read who asked you to chant, water fell fragrance floating. ';
</script>

demo2.php

<?php
  //deep understanding of ECHO, Echo is a function
  //echo function: Return value to browse output string
  //echo: void no return value
  Echo ' read who asked you to chant, water fell fragrance floating ';
  Print function: Output A string to the browser.
  //print return value: Integer
  echo ' <br/> ';
  print ' read who asked you to chant, water fall fragrance floating. ';
  Echo ' <br/> ';
  echo print ' Read who asked you to chant, water fell fragrance floating. ';
  printf feature: Output a string to the browser.
  //printf return value: Returns the length of the string
  echo ' <br/> ';
  printf ("Buy%d Discs", 5);
  Echo ' <br/> ';
  echo printf ("Purchase%d discs", 5);
  sprintf function: Keep string in memory
  //sprintf return value: Returns the string itself
  echo ' <br/> ';
  echo sprintf ("Purchase%d discs", 5);
? >

demo3.php

<?php
  //Create a variable
  //What type, Integer, string, floating-point type, Boolean
  ///create variable by assigning value to determine its type
  $sum = 0;
  $total = 1.22;
  $sum = $total;
  echo $sum;
? >

demo4.php

<?php
//data type conversion
//$sum = 0;
$total = 1.22;
$sum = $total;//An implicit conversion
//echo $sum;
  $sum = 0;
  $total = $sum;
  Echo GetType ($total);
  echo "<br/>";
  $total = (float) $sum; Explicit conversion of
  Echo GetType ($total);
? >

demo5.php

<?php
  //set type Settype ()
  $sum = m;
  Converts the $sum type into a string
  settype ($sum, "string") halfway through;
  This time $sum 100 is not a number, but a string of "
  GetType" Echo ($sum);
? >

demo6.php

<?php
  //isset () and unset ()
  //judge whether a variable exists/
  destroy a variable
  $a = 5;
  Variable $a already exists
  unset ($a);
  If $a this variable is real, then isset ($a) returns a Boolean value of 1, an empty
  echo isset ($a);
  $b = 0;
   Empty () is used to determine whether the value of a variable is null, or False if NULL is true.
  //In other words, "", 0, "0", NULL, FALSE, Array (), var var ();
  and objects without any attributes will be considered null
  echo empty ($b);
? >

demo7.php

<?php
  //Type judgment function
  $sum =;
  echo Is_integer ($sum);
? >

demo8.php

<?php
  //$sum is a floating-point type
  $sum = 22.22;
  Intval ($sum) became integral type
  //echo intval ($sum);
  Settype ($sum, "integer");
  echo $sum;
  May I ask $sum what type of
  Echo GetType is currently ($sum);
? >

demo9.php

<?php
  //constants are defined by the define () to define
  define ("Total");
  echo Total;
  $TOTAL =;
  echo $TOTAL;
  echo $_server["Server_admin"];
  echo $_server["Http_host"];
  Echo Phpinfo ();
? >

demo10.php

<meta http-equiv= "Content-type" content= "text/html; CHARSET=GBK ">
<form method=" Get "action=" demo11.php ">
  name: <input type=" text "name=" username "/ >
  <input type= "Submit" value= "submitted"/>
</form>

demo11.php

<?php
  //echo $username; this short style is not allowed to use
  //It will confuse the relationship with the normal variable,//the
  first step is to assign the variable data received to a variable
  ///The previous table is given the name of the Value is extracted value= "CHAOYV" name= "username"
  //$_post[' username '] This whole will return "CHAOYV" This string
  //echo ' $_post[' Username '];
$username = $_post[' username '];
echo $username;
$username = $HTTP _post_vars[' username '];
echo $username;
  echo $_get[' username '];
? >

More about PHP Interested readers can view the site topics: "Introduction to PHP Basic Grammar", "PHP operation and operator Usage Summary", "PHP object-oriented Program Design Primer", "PHP Network Programming Skills Summary", "PHP string (String) Usage Summary", " Introduction to PHP+MYSQL Database operations and a summary of PHP common database operations Tips

I hope this article will help you with the PHP program design.