


There are some functions in PHP that can be used to sort arrays. But for an array with multiple fields, how to sort by specified fields? You can use the array_multisort function to sort by specified fields.
There are some functions in PHP that can be used to sort arrays.
sort() - Sort the array in ascending order
rsort() - Sort the array in descending order
asort() - Sort an array in ascending order based on the values of the associative array
ksort() - Sort the array in ascending order based on the keys of the associative array
arsort() - Sort an array in descending order based on the values of an associative array
krsort() - Sort an array in descending order based on the keys of an associative array
For example:
$arr=['green','car','apple','book']; sort($arr); var_dump($arr);
You can get the sorting result:
array (size=4) 0 => string 'apple' (length=5) 1 => string 'book' (length=4) 2 => string 'car' (length=3) 3 => string 'green' (length=5)
But for an array with multiple fields, how to sort according to the specified field What? For example, the following array:
$arr=[ [ 'age'=>50, 'name'=>'张三' ], [ 'age'=>18, 'name'=>'李四' ], [ 'age'=>27, 'name'=>'王五' ] ];
How do we sort by age or name? We can use the array_multisort function to sort by specified fields.
array_multisort(array_column($arr,'age'),SORT_ASC,$arr); var_dump($arr);
Print results
array (size=3) 0 => array (size=2) 'age' => int 18 'name' => string '李四' (length=6) 1 => array (size=2) 'age' => int 27 'name' => string '王五' (length=6) 2 => array (size=2) 'age' => int 50 'name' => string '张三' (length=6)
This way, it is sorted. That is to say, when sorting using the array_multisort function, use array_column to sort the column specified by the array to extract the first parameter and put the sorting constant If you put the second parameter and the array into the third parameter, you can sort by the specified field. SORT_ASC is ascending order, SORT_DESC is descending order.
Recommended learning: php video tutorial
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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。


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