How to get the value of the first array cell in php_PHP tutorial

This article mainly explains how to get the value of the first array unit of an array in PHP. Among PHP's built-in functions, the main functions for obtaining array element values ​​include reset next current prev end.

reset (PHP 3, PHP 4, PHP 5)

Function definition mixed reset (array &array)

Function: This function rewinds the internal pointer of array to the first unit and returns the value of the first array unit. If the array is empty, it returns FALSE. For example:

<?php
$array=array('step one','step two','step three','step four');
echo reset($array);
//输出：step one

next (PHP 3, PHP 4, PHP 5)

Function definition mixed next (array &array)

Function: Return the value of the next unit pointed to by the internal pointer of the array, or return FALSE when there are no more units. For example:

<?php
$array=array('step one','step two','www','phpernote.com','step four');
echo next($array);
//输出：step two

Warning: If the array contains empty cells, or the value of the cell is 0, this function will also return FALSE when encountering these cells. To correctly iterate over an array that may contain empty cells or a cell value of 0, see the each() function.

current (PHP 3, PHP 4, PHP 5)

Function definition mixed current (array &array)

Function: Returns the value of the array unit currently pointed to by the internal pointer, without moving the pointer. Initial points to the first element inserted into the array. If the internal pointer points beyond the end of the cell list, current() returns FALSE.

Warning: If the array contains an empty cell (0 or "", empty string), this function will also return FALSE when encountering this cell. This makes it impossible to tell with current() whether the end of this array list has been reached. To correctly iterate over an array that may contain empty cells, use the each() function.

next() behaves similarly to current(), except that the internal pointer is moved forward one position before returning the value. This means that it returns the value of the next array element and moves the array pointer forward one position. If moving the pointer results in moving the pointer beyond the end of the array element, next() returns FALSE.

The following are examples of related functions:

<?php
$transport = array('foot', 'www', 'car', 'phpernote','com');
$mode = current($transport); // $mode = 'foot';
$mode = next($transport); // $mode = 'www';
$mode = next($transport); // $mode = 'car';
$mode = prev($transport); // $mode = 'www';
$mode = end($transport); // $mode = 'com';
$mode = current($transport); // $mode = 'com';
$mode = reset($transport); // $mode = 'foot';

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