打印所有可能的条件组合？

Question

我有这些变量：

$letters = array('a','b','c','1','2','3', .....);
$min_length = any number ;
$max_length = any number;
$must_include = array('letter1','letter2', .....); // list of letters and numbers that must be in combination
$must_exclude = array('letter3','letter3', .....); // list of letters and numbers that must not be in combination

我需要一个函数来根据给定的变量打印所有可能的组合。

我怎样才能完成这项任务？

Answer 1

这个孤立的问题可以使用 php 的array_* 函数来解决。

1. 首先，让我们定义变量：

   $letters = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9');
   $min_length = 5;
   $max_length = 15;
   $must_include = array('a','e', 't', '7');
   $must_exclude = array('4','q', 'j', '9');
   

2. 为了更简单的解决方案，让我们根据$min_length 和$max_length 值定义一个固定长度的结果作为变量：

   $actual_length = rand($min_length, $max_length);
   

3. 下一步，让我们通过删除and来准备干净的字母：

   $clean_letters = array_diff($letters, $must_exclude);
   $clean_letters = array_diff($letters, $must_include);
   

   请注意，我删除$must_include 和$must_exclude 的原因是，稍后我将在结果中包含$must_include，因为它必须包含在内。

4. 现在来看实际结果：

   $result = $must_include;
   $result = array_merge($result, array_rand($letters, $actual_length - sizeof($result)));
   

   在这一步中，我默认$result 为$must_include，然后将其与$letters 的随机值合并为$actual_length 的大小减去$must_include 的大小。

上述所有步骤将产生在$must_include 中始终包含字母并省略$must_exclude 字母的值。

完整脚本如下：

<?php

$letters = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9');
$min_length = 5;
$max_length = 15;
$must_include = array('a','e', 't', '7');
$must_exclude = array('4','q', 'j', '9');

$actual_length = rand($min_length, $max_length);

echo "Length: " . $actual_length . ".\n";


if( count(array_intersect($must_include, $must_exclude)) > 0 ){
    die("Value in $must_include MUST NOT present in $must_exclude.\n");
}

if( count(array_intersect($must_exclude, $must_include)) > 0 ){
    die("Value in $must_exclude MUST NOT present in $must_include.\n");
}

if(sizeof($must_include) > $min_length){
    die("\$min_length MUST BE larger or equal to \$must_include.\n");
}

if(!$actual_length <= $max_length || $actual_length >= $min_length){
} else {
    die("\$actual_length MUST BE between \$min_length to \$max_length.\n");
}

$clean_letters = array_diff($letters, $must_exclude);
$clean_letters = array_diff($letters, $must_include);

// echo implode(", ", $clean_letters) . "\n";

$result = $must_include;
$result = array_merge($result, array_rand($letters, $actual_length - sizeof($result)));


echo "Must Include: " . implode(", ", $must_include) . "\n";
echo "Must Exclude: " . implode(", ", $must_exclude) . "\n";
echo "Result (" . sizeof($result) . "): " . implode(", ", $result) . "\n";