


Regarding sorting, generally we sort through the database or nosql (eg: redis) and then output it to the program for direct use. However, sometimes we need to sort the array directly through PHP and store the data in PHP. The most used ones are objects and arrays, but the ones that are processed the most are arrays, because there are very rich built-in function libraries (in fact, objects can also be understood as arrays to a certain extent). These function libraries can largely help us achieve certain features. Commonly used system functions include sort, asort, arsort, ksort, krsort, etc. Here I mainly talk about the two methods of sorting two-dimensional arrays:
1. Use PHP’s own array_multisort function to sort
$data = array();
$data[] = array('volume' => 67, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 1);
$data[] = array('volume' => 85, 'edition' => 6);
$data[] = array ('volume' => 98, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 6);
$data [] = array('volume' => 67, 'edition' => 7);
// Get the list of columns
foreach ($data as $key => $row)
{
$volume[$key] = $row['volume'];
$edition[$key] = $row['edition'];
}
array_multisort($volume, SORT_DESC, $edition, SORT_ASC, $data);
print_r($data);
?>
Output result:
(
[0] => Array
(
( t; 86
[ edition] => 1
)
[2] => Array
(
[volume] => 86
[edition] => 6
)
[3] => Array
(
[volume] => 85
[edition] => 6
)
[4] => Array
(
[volume] => 67
[edition] => 2
)
[5] => Array
(
[vol ume] => 67
The official document about array_multisort also has a more detailed description: http://www.php.net/manual/zh/function.array-multisort.php
2. Custom function sorting 1
$data = array();
$data[] = array('volume' => 67, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 1);
$data[] = array('volume' => 85, 'edition' => 6);
$data[] = array('volume' => 98, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 6);
$data[] = array('volume' => 67, 'edition' => 7);
// 取得列的列表
foreach ($data as $key => $row)
{
$volume[$key] = $row['volume'];
$edition[$key] = $row['edition'];
}
$ret = arraySort($data, 'volume', 'desc');
print_r($ret);
/**
* @desc arraySort php two-dimensional array sorting sorts the array according to the specified key
* @param array $arr The array to be sorted
* @param string $keys Specifies the sorting key
* @param string $type Sorting type asc | desc
* @return array
*/
function arraySort($arr, $keys, $type = 'asc') {
$keysvalue = $new_array = array();
foreach ($arr as $k => $v){
$keysvalue[$k] = $v[$keys];
}
$type == 'asc' ? asort($keysvalue) : arsort($keysvalue);
reset($keysvalue);
foreach ($keysvalue as $k => $v) {
$new_array[$k] = $arr[$k];
}
return $new_array;
}
?>
输出结果:
(
[3] => Array
(
[volume] => 98
[edition] => 2
)
[4] => Array
(
[volume] => 86
[edition] => 6
)
[1] => Array
(
[volume] => 86
[edition] => 1
)
[2] => Array
(
[volume] => 85
[edition] => 6
)
[5] => Array
(
[volume] => 67
[edition] => 7
)
[0] => Array
(
[volume] => 67
[edition] => 2
)
)
One difference between this custom function and the system function is that the custom function only supports sorting for a certain key. If you want to support sorting for multiple keys, you need to execute it multiple times; while the system function array_multisort can sort multiple keys at once. key and can specify multiple sorting rules. The system function is quite powerful. It is recommended to use the system function. After all, it is implemented at the bottom of C. Here is just an example to illustrate how to sort the array through a custom function. Of course, this custom function can also be used. Continue to expand to support more collations. It is still used a lot in scenarios such as rankings, leaderboards, and results.
3. Custom function sorting 2
The following function sorts a given two-dimensional array according to the specified key value. Let’s look at the function definition first:
function array_sort($arr,$keys,$type='asc'){
$keysvalue = $new_array = array();
foreach ($arr as $k= >$v){
$keysvalue[$k] = $v[$keys];
}
if($type == 'asc'){
asort($keysvalue);
}else{
arsort($keysvalue);
}
reset($keysvalue);
foreach ($keysvalue as $k=>$v){
$new_array [$k] = $arr[$k];
}
return $new_array;
}
It can sort the two-dimensional array according to the specified key value, or you can specify Ascending or descending sorting method (default is ascending order), usage example:
$array = array (
array('name'=>'Mobile phone','brand'=>'Nokia','price'=>1050),
array('name'=>'Laptop' ,'brand'=>'lenovo','price'=>4300),
array('name'=>'razor','brand'=>'Philips','price' =>3100),
array('name'=>'Treadmill','brand'=>'Sanwa Soushi','price'=>4900),
array('name '=>'Watch','brand'=>'Casio','price'=>960),
array('name'=>'LCD TV','brand'=>' Sony','price'=>6299),
array('name'=>'Laser Printer','brand'=>'HP','price'=>1200)
) ;
$ShoppingList = array_sort($array,'price');
print_r($ShoppingList);
The above is the two-dimensional array $array according to 'price' from low to High sort.

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。

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。

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。

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。


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