PHP Questions and Answers

Use a function  array_slice($array,1)

array_slice() returns the sequence of elements from the array array as specified by the offset and length parameters

$array=array_flip($array)

Exchanges all keys with their associated values in an array

array_flip() returns an array in flip order, i.e. keys from trans become values and values from trans become keys.

$browser = get_browser(null, true);
print_r($browser);

&

echo $_SERVER[‘HTTP_USER_AGENT’] . “\n\n”;

chmod($image, 755);

3306

Hooks are provided by WordPress to allow your plugin to ‘hook into’ the rest of WordPress; that is, to call functions in your plugin at specific times, and thereby set your plugin in motion.

There are two kinds of hooks:

1. Actions: Actions are the hooks that the WordPress core launches at specific points during execution, or when specific events occur. Your plugin can specify that one or more of its PHP functions are executed at these points, using the Action API. Eg: for action functions are add_action().

2. Filters: Filters are the hooks that WordPress launches to modify text of various types before adding it to the database or sending it to the browser screen. Your plugin can specify that one or more of its PHP functions is executed to modify specific types of text at these times, using the Filter API. Eg: for filter functions are add_filter().

If you look at the large variety of SQL commands, they can be divided into three large subgroups.

Data Definition Language deals with database schemas and descriptions of how the data should reside in the database, therefore language statements like CREATE TABLE or ALTER TABLE belong to DDL.

DML deals with data manipulation, and therefore includes most common SQL statements such SELECT, INSERT, etc.

Data Control Language includes commands such as GRANT, and mostly concerns with rights, permissions and other controls of the database system.

The JOIN keyword is used in an SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables.

The difference is in the way tables are joined if there are no common records.

JOIN is same as INNER JOIN and means to only show records common to both tables. Whether the records are common is determined by the fields in join clause. For example:

FROM t1
JOIN t2 on t1.ID = t2.ID

means show only records where the same ID value exists in both tables.

LEFT JOIN is same as LEFT OUTER JOIN and means to show all records from left table (i.e. the one that precedes in SQL statement) regardless of the existance of matching records in the right table.

RIGHT JOIN is same as RIGHT OUTER JOIN and means opposite of LEFT JOIN, i.e. shows all records from the second (right) table and only matching records from first (left) table.

This function will turn output buffering on. While output buffering is active no output is sent from the script (other than headers), instead the output is stored in an internal buffer. The contents of this internal buffer may be copied into a string variable using ob_get_contents(). To output what is stored in the internal buffer, use ob_end_flush(). Alternatively, ob_end_clean() will silently discard the buffer contents.

Copy Makes a copy of a file. Returns TRUE if the copy succeeded otherwise return FALSE.

move_uploaded_file() function checks to ensure that the file designated by filename is a valid upload file. If the file is valid, it will be moved to the filename given by destination. If filename is not a valid upload file, then no action will occur, and move_uploaded_file() will return FALSE.