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PHP基本语法快速入门

2013-05-31 22:01 561 查看

PHP基础文法快速入门

Perl的和Ruby的语法组织得非常好，于是PHP也跟着尝试将这两种语言的优势引入。

Grammar list of Perl and Ruby was so very well organized, I tried to do any PHP Taking advantage of.

The Perl with Perl Beginner to Beginner to sample code - Perl basic grammar fastest master
Route 477 - Ruby basic grammar fastest master
I think people who know something about other languages can understand somehow the PHP syntax If you are reading this.

Please tell us mistake, if any shortage etc. m (__) m

Version

PHP5.3 system has been released, but is intended for PHP5.2 system here.

1. Basis

代码块Code block

PHP code begins with the start tag of "<? Php". End tag is "?>". Use the end tag when you fill the PHP code in HTML, omitting the end tag has become a convention when writing the only PHP code as a library.

It had positive commentary on Kiske's: id reason for omitting the end tag. Thank you.

PHP 基本语法最快入门补充 - Absolute Playing!

<?php $I = 1; hoge ($I); ?>
<?php hoge (); ?>

打印语句print statement

I use the print / echo.

<?php
"! Hello World" Print;
"! Hello World" echo;
?>

I often use var_dump () to debug. contents of the variable in var_dump () is output.

<?php
$array = array (1,2,3);
var_dump ($array);

?>

array (3) {

[0] =>

int (1)

[1] =>

int (2)

[2] =>

int (3)

}

注释Comment

单行注释(Line Comments)

<?php
//comment
# comment
?>

多行注释 Multi-line comments

<?php
/ *
comment
comment
* /
?>

变量声明Variable declarations

It is a declaration of the variable.

<?php
$a = 'string';
$I = 1;
?>

脚本的执行(Execution of the script)

I run a PHP file on the command line.

$ php hoge.php

You can also write directly to the PHP code. <? Php?> Is not required.

$ php-r "var_dump ('a');"

Use the redirect to write the output to a file results.

$ php hoge.php> out

词法检查(Grammar check of the script，lex)

I can check grammar in php command.

$php -l hoge.php

2. 数值 Numerical

Representation of the number

There integer, floating-point to a number.

<?php
$int = 100;
$float = 100.123;
?>

4种算术操作 Four arithmetic operations

<?php
$I = 1 + 1;
$I = 1 - 1;
$I = 1 * 1;
$I = 1/2;
?>

Quotient and remainder. Remove the integer part in the intval function after performing the division of normal order to obtain the quotient.

<?php
$div = intval (3/2); //quotient
$mod = 3 % 2; // remainder
?>

Increment and decrement

<?php
$I + +; //increment
$i --; //decrement
?>

3. 字符串 String

String representation

I must be enclosed in either single or double quotes is a string. You can use special characters, and \ n (tab), such as (newline) \ t is in double quotes. In addition, it can be variable expansion within a character string enclosed in double quotes.

<?php
$str1 = "abc\tcde";   // (\ t tabs [0x09]) //abc cde;
$str2 = 'abc\tcde';  // (string \ t) abc \ tcde
$str3 = "$str1 100"; // abc cde 100 // $st1 will be replaced
$str4 = "{$str1} 100"; // when the string leads to a variable name enclosed in {}
?>

字符串操作String operation

<?php
//join
$Join1 = 'aaa' 'BBB';.
$Join2 = Implode (',', array ('aaa', 'BBB', 'ccc'));
//Split
$split = explode (',', 'aaa, bbb, ccc');
//Length
$length = strlen;('abcdef')
//(multi-byte) length
setting of //internal encoding is necessary
//mb_internal_encoding ('UTF-8');
$mb_length = mb_strlen('tails ABC');
//Cut
$substr = substr ('abcd', 0, 2); //ab
//Search
$index = strpos ('abcd', 'bc'); //Once you have located the position return false if you do not find (the first is 0),
?>

4. 数组与关联数组Array, associative array

There are only associative array with PHP. Array is represented as an associative array of numbers is key. I also have the order.

<?php
$array1 = array (1, 2, 3); //array (associative array key starts from 0)
$array2 = array ('a' => 1, 'b' => 2, 'c' = > 3); //associative array (1, 'a' => 1, 2)
$array3 = array; //mixed also OK
?>

Assignment of a reference element

<?php
$i = $array1[0];
$s = $array2['a'];
?>
<?php
$array1[3] = 1;
$array2['z'] = 'zzz';
?>

The number of elements

<?php
$len = count ($array1);
?>

Operation of the array

<?php
$array = array (1, 2, 3);
//retrieve thetop
$first = array_shift ($array); //$first = 1, $array is, (2, 3);
//added to thetop
array_unshift ($array, 5); //$array is, (5, 2, 3)
// to remove the end
$last = array_pop ($array); //the array is (5, 2 ) , $last = 3;
// Add to the end
array_push ($array, 9); // $array is, (5, 2, 9)
?>

关联数组函数The function of associative array

<?php
//obtain key
$keys = array_keys ($array);
//obtain value
$values = array_values ($array);
//key presence confirmation of
$boolean = array_key_exists ('key', $array);
//Delete the key
unset ($array ['key']);
?>