PHP Notes: Use of PHP Array Related Functions_PHP Tutorial-PHP Tutorial-php.cn

PHP Notes: Use of PHP Array Related Functions_PHP Tutorial

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Release： 2016-07-21 15:12:18

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创建数组就不再说了 array()函数

提取数组可以用list().

测试数组元素 ,可以用is_array()

接受一个参数,传进来的变量,如果变量是数组,返回true如果不是返回false.

添加和删除数组元素

数组的fifo和lifo

先解释下什么是fifo和lifo

删除元素与加入元素的顺序相同,称为先进先出,既first-in-first-out

删除元素与加入元素的顺序相反,称为后进先出,既last-in-first-out

相对应的对数组的操作

array_unshift()
int aray_unshift(array array,mixed variable [,mixed variable...])

在数组头添加元素,所有已有的数值键都会相应的改变,以反映在数组中的新位置,关联键不受影响.

例:

$words = array('a','b','c');

print_r($words);

//array([0]->a,[1]->b,[2]->c);

array_unshift($words,'d');

print_r($words);

//array([0]->d,[1]->a,[2]->b,[3]->c);

array_shift()
mixed array_shift(array array)

从数组头删除元素,删除并返回数组中找到的元素,结果是,如果使用的是数值键,则所有相应的值都会下移.如果使用的是关联键,数组不受影响.

例:

$words = array('a','b','c');

print_r($words);

//array([0]->a,[1]->b,[2]->c);

array_shift($words,'a');

print_r($words);

//array([0]->b,[1]->c);

array_push()
int array_push(array array ,mixed variable [,mixed variable...])

从数组尾添加元素,将variable添加到数组的末尾,成功返回true 失败返回false.可以传递多个参数,作为输入,同时向数组压入多个变量.

例:

<span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #000000"><span style="FONT-FAMILY: Courier New"><span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb"><?php<BR style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif">$stack </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">= array(</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #dd0000">"orange"</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">, </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #dd0000">"banana"</SPAN></SPAN><SPAN style="FONT-FAMILY: Courier New"><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">);<BR style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif"></SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">array_push</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">(</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">$stack</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">, </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #dd0000">"apple"</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">, </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #dd0000">"raspberry"</SPAN></SPAN><SPAN style="FONT-FAMILY: Courier New"><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">);<BR style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif"></SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">print_r</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">(</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">$stack</SPAN></SPAN><SPAN style="FONT-FAMILY: Courier New"><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">);<BR style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif"></SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">?></span></span></span>

本例将使 $stack 具有如下单元：

Array ( [0] => orange [1] => banana [2] => apple [3] => raspberry )

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上例摘自PHP手册.对于数组操作,使用$array[]=,可以增加效率.因为不需要调用函数.

--------------------聪明的分割线-----------------------------

array_pop()
mixed array_pop(array target_array)

从数组末尾删除元素并返回数组的最后一个元素.

<span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #000000"><span style="FONT-FAMILY: Courier New"><span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb"><?php<BR style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif">$stack </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">= array(</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #dd0000">"orange"</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">, </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #dd0000">"banana"</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">, </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #dd0000">"apple"</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">, </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #dd0000">"raspberry"</SPAN></SPAN><SPAN style="FONT-FAMILY: Courier New"><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">);<BR style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif"></SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">$fruit </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">= </SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">array_pop</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">(</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">$stack</SPAN></SPAN><SPAN style="FONT-FAMILY: Courier New"><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">);<BR style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif"></SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">print_r</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">(</SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">$stack</SPAN></SPAN><SPAN style="FONT-FAMILY: Courier New"><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #007700">);<BR style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif"></SPAN><SPAN style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">?></span></span></span>

经过此操作后，$stack 将只有 3 个单元：

Array ( [0] => orange [1] => banana [2] => apple )

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The above example is taken from the PHP manual

-------------------------Smart dividing line------------------

Some of my own summaries and opinions.

The above four functions may be very useful sometimes. Let’s talk about the return value first

Note that the return value of array_unshift() and array_push() should be of boolean type, but the manual and related books indicate that the returned value is int type. This is worth thinking about.

The two functions array_shift() and array_pop() can not only delete the elements of the relevant array, but also return the deleted array elements. I will write it here first, there will be more to come. Let’s summarize slowly.