PHP and Mysql web application development core technology Part 1 Php basics-1 Start to understand php_PHP tutorial

1.1 The first php

Copy code The code is as follows:

echo "Hello Everybody!";
?> ;

Additional: usage of phpinfo() function
1.2 Enter php script
1.2.1 Mark php code Paragraphs
1.2.2 Statements and comments
/* */
//
#
#
1.2.3 Mixing php and html
1.3 How to store data
1.4 Enter the basic data types of PHP
1.4.1 Numbers: (integers (int) and floating point numbers (float)) Octal represents a number that must be preceded by 0 (zero), hexadecimal represents a number that must be preceded by 0x .
Note: 1 When operating with floating point numbers, only approximate values ​​will be taken
2 5/2＝2.5 If you want to take an integer, use the round() function
1.4.2 String
Single quotes: ' ', To include a single quote in a string, just precede it with a backslash.
The simplest way to define a string is to surround it with single quotes (punctuation mark ').
To output a single quote, add a backslash () in front of it. To output a backslash before a single quote or at the end of a string, enter two (\)
Note that if a backslash is added before any other character, the backslash will be output directly. .
Double quotes " "
Escaped characters Meaning
n Line feed (LF or 0x0A (10) in ASCII)
r Carriage return (CR or 0x0D (13) in ASCII)
t Horizontal tab (HT or 0x09 (9) in ASCII)
v Vertical tab (VT or 0x0B (11) in ASCII) (since PHP 5.2.5)
f Page feed (FF or 0x0C (12) in ASCII) (since PHP 5.2.5)
\ backslash
$ dollar mark
" double quotes
[0-7]{1,3} conforms to this expression The string in the order of the expression is an octal character
x[0-9A-Fa-f]{1,2} The string in the order of the expression is a hexadecimal character
1.5 Some in Very useful function
1.5.1 nl2br: Insert html newline character after each new line (n) in the string

Copy code The code is as follows :

echo nl2br("foo isn'tn bar");
?>

1.5.2 var_dump: View Types and variable values
1.5.3 print_r: Return the result to a string instead of outputting the result to the output stream. This user-friendly output is especially useful for objects and arrays
print_r() Displays human-readable information about a variable. If given as a string, integer, or float, the variable value itself will be printed.
If given as an array, the keys and elements of the array will be displayed. Similar.
1.5.4 var_export: It is similar to var_dump, except that its output is actually a valid php code representation of the provided data value

Copy code The code is as follows:

$arr=array(1,2,3,4);
var_exprot($arr);
? >

http://www.bkjia.com/PHPjc/323904.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/323904.htmlTechArticle1.1 The first php copy code is as follows: html head titleMy First PHP Program/title /head body ?php echo "Hello Everybody!"; ? /body /html Additional: Usage of phpinfo() function 1.2 Input...