如何提取两个指定键之间的元素范围？

Question

我有两个数组，第一个是：

Array (
  [0] => Mar
  [1] => Jun
)

第二个是：

Array (
  [Jan] => January
  [Feb] => February
  [Mar] => March
  [Apr] => April
  [May] => May
  [Jun] => June
  [Jul] => July 
  [Aug] => August
  [Sep] => September
  [Oct] => October
  [Nov] => November
  [Dec] => December
)

我想提取搜索数组中从第一个指定月份到第二个指定月份的元素。

我的预期结果是：

Array (
  [Mar] => March
  [Apr] => April
  [May] => May
  [Jun] => June
)

Answer 1

请查看下面的答案，或许对您有所帮助：

$fullArray = [
    'Jan' => 'January',
    'Feb' => 'February',
    'Mar' => 'March',
    'Apr' => 'April',
    'May' => 'May',
    'Jun' => 'June',
    'Jul' => 'July',
    'Aug' => 'August',
    'Sep' => 'September',
    'Oct' => 'October',
    'Nov' => 'November',
    'Dec' => 'December',
];


$arrayToCompare = [
    'Mar', 'Jun'
];



$matchedArray = array();

$matchedFirst = false;
$matchedLast = false;

foreach ($fullArray as $key => $value) {
    if ($key == $arrayToCompare[0]) {
        $matchedFirst = true;
    }

    if ($key == $arrayToCompare[1]) {
        $matchedLast = true;
    }

    if ($matchedFirst == true) {
        $matchedArray[$key] = $value;
    }

    if ($matchedLast == true) {
        $matchedArray[$key] = $value;
        break;
    }

}

print_r($matchedArray);
die;

Answer 2

如果没有带条件的 foreach 循环，可以更优雅地编写一个简洁的解决方案。
我将提供几个干净的方法，每个方法只利用四个数组函数调用。

输入：

$months=[
    'Jan' => 'January',
    'Feb' => 'February',
    'Mar' => 'March',
    'Apr' => 'April',
    'May' => 'May',
    'Jun' => 'June',
    'Jul' => 'July',
    'Aug' => 'August',
    'Sep' => 'September',
    'Oct' => 'October',
    'Nov' => 'November',
    'Dec' => 'December'
];
$range=['Mar','Jun'];

方法#1：（仅两行代码和四个函数）Demo

// create indexed array of keys in $month, retain only 2 selected months, get their indexes
$a=array_keys(array_intersect(array_keys($months),$range));
// slice the desired elements using offset and calculated length
var_export(array_slice($months,$a[0],$a[1]-$a[0]+1));

方法#2（仅四行代码和四个函数）Demo

$indexes=array_keys($months);  // generate an indexed array of abbreviated months
$start=array_search($range[0],$indexes);  // get the index of the starting month
$length=array_search($range[1],$indexes)-$start;  // subtract start from end month index
var_export(array_slice($months,$start,$length+1));  // extract the desired elements

输出：（使用任一方法）

array (
  'Mar' => 'March',
  'Apr' => 'April',
  'May' => 'May',
  'Jun' => 'June',
)

如何提取两个指定键之间的元素范围？

How to extract a range of elements between two specified keys?

php

arrays

range

offset

slice