This time I will bring you a method to quickly implement array deduplication in PHP. What are the precautions to quickly implement array deduplication in PHP? The following is a practical case, let's take a look.
Overview
Using PHP’sarray_unique<a href="http://www.php.cn/wiki/1027.html" target="_blank">()</a> function allows you to pass an array, Then remove duplicate values and return an array with unique values. This function works well most of the time. However, if you try to use the
array_unique() function on a large array, it will run slower.
array_flip() instead of using the
array_unique() function to create a unique array. This magical function will swap the key and value of each element in the array, because the key value must be unique, therefore, you will get the same result as the
array_unique() function.
/* 创建一个包含重复值的,一共四个元素的数组 */ $array = array('green','blue','orange','blue'); /* 翻转数组,你将会得到唯一键值的数组 array('green'=>0,'blue'=>1,'orange'=>2); */ $array = array_flip($array); /* 然后再翻转一次,将键和值重新放置,然后得到数组:array(0=>'green',1=>'blue',2=>'orange'); */ $array = array_flip($array); print_r($array)Running result:
Array ( [0] => green [3] => blue [2] => orange )Because we have removed some elements, the array does not look like a normal sequence. For example, we may get:
array(0=>'A',2=>'B',5=>'C');. In some cases, this is not a problem, but if you need the array keys to remain in numerical order, you can use one or two methods to solve the problem of key values being out of order.
Use array_merge to repair the keys of the array
The function after addingarray_flip will sort the keys of the array and restore them to normal sequence, such as: 0,1,2,3...
$array = array('green','blue','orange','blue'); $array = array_flip($array); $array = array_flip($array); /* 使用array_merge()函数修复键值*/ $array = array_merge($array); print_r($array)The running result is the same as above
The second way is to use array_keys
Note that this method of repairing array key values is slightly faster than using thearray_merge() function. You can also use the
array_keys() function in conjunction with the last step (this function returns the flipped value). Then when you flip the values in the array, the keys are created in order.
$array = array('green','blue','orange','blue'); $array = array_flip($array); /* 跟第一个例子一样,但是现在我们先提取数组的键值 */ $array = array_keys($array); print_r($array)I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website! Recommended reading:
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The above is the detailed content of PHP quickly implements array deduplication method. For more information, please follow other related articles on the PHP Chinese website!

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。


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