如何减少数组值中的一部分？

Question

我有一个格式为

array() {["2011-07-29"]=> 39 ["2011-07-30"]=> 39 ["2011-07-31"]=> 39 ["2011-08-01"]=> 40}

我需要 t0 将中间键值递减 1 的数组，即 ["2011-07-29"] 到 ["2011-06-29"]

输出应该

array() {["2011-06-29"]=> 39 ["2011-06-30"]=> 39 ["2011-06-31"]=> 39 ["2011-07-01"]=> 40}

怎么做？

Answer 1

就像 Fernaref 解释的那样：通过解析键的值来根据您的需要更改键。有多种方法可以实现这一目标，这只是一个示例（演示）：

<?php

$data = array(
  '2011-07-29' => 39,
  '2011-07-30' => 39,
  '2011-07-31' => 39,
  '2011-08-01' => 40,
);

$keys = array_keys($data);

foreach($keys as &$key)
{
    list(,$month) = sscanf($key, '%d-%d-%d');
    $month = sprintf("%02d", $month-1);
    $key[5] = $month[0];
    $key[6] = $month[1];
}
unset($key);

$data = array_combine($keys, $data);

print_r($data);

Answer 2

它是一个字符串 - 您必须解析数据，递减值并将密钥重新组合在一起。或者首先使用更好的密钥。

Answer 3

试试这个：

$result = array();
foreach ($array as $key => $val) {
  $date = strtotime ($key);

  $result[date("Y-m-d", strtotime("- month", $date)] = $val;
}

Answer 4

$input = array("2011-07-29"=>39, "2011-07-30"=>39, "2011-07-31"=>39, "2011-08-01"=>40);
$output = array();

foreach($input as $key => $value) {
    $key = preg_replace_callback("/(\d{4})-(\d{2})-/", function($match) {
        $match[2] = (int) $match[2] - 1;
        if( $match[2] < 1 ) { // don't forget to decrement the year, if the month goes below 1
            $match[1] = (int) $match[1] - 1;
            $match[2] = 12;
        }
        return $match[1] . "-" . str_pad($match[2], 2, "0", STR_PAD_LEFT) . "-";
    }, $key);
    $output[$key] = $value;
}

print_r($output);

Answer 5

某些功能可以是

preg_replace("@(\d\d\d\d)-(\d\d)@e","'\$1-'.str_pad($2-1, 2, '0', STR_PAD_LEFT)",$key);

Answer 6

$newArray = array();
foreach ($array as $key => $value)
{
  $newKey = someFunction($key);
  $newArray[$newKey] = $value;
}

而“someFunction”将转换您的日期以创建新密钥