PHP将位数组压缩为尽可能短的字符串 [英] PHP Compress array of bits into shortest string possible

问题描述

我有一个数组，其中包含代表真值或假值的1或0值.例如

I have an array that contains values of 1 or 0 representing true or false values. e.g.

array(1,0,0,1,0,1,1,1,1);

我想将此数组压缩/编码为尽可能短的字符串，以便可以将其存储在空间受限的位置(例如cookie)中.还需要稍后能够再次对其进行解码.我该怎么办?

I want to compress/encode this array into the shortest string possible so that it can be stored within a space constrained place such as a cookie. It also need to be able to be decoded again later. How do I go about this?

ps.我正在使用PHP

ps. I am working in PHP

推荐答案

这是我的建议:

$a = array(1,0,0,1,0,1,1,1,1,1,0,0,1,0,1,1,1,1,1,0,0,1,0,1,1,1,1);

$compressed = base64_encode(implode('', array_map(function($i) {
    return chr(bindec(implode('', $i)));
}, array_chunk($a, 8))));

var_dump($compressed); // string(8) "l8vlBw=="

因此，您获得了每个8个字符(实际上是二进制 0..255 )，将它们转换为整数，表示为ASCII字符，将其内嵌到字符串中并转换为base64以便将其另存为字符串.

So you get each 8 characters (which in fact is a binary 0..255), convert them to an integer, represent as an ASCII character, implode it to a string and convert to base64 to be able to save it as a string.

UPD :

相反的方法很简单:

$original = str_split(implode('', array_map(function($i) {
    return decbin(ord($i));
}, str_split(base64_decode($compressed)))));

我写得怎么样了(以防万一有人有兴趣写这样的不可读且几乎无法维护的代码):

How exactly I wrote it (just in case anyone interesting how to write such unreadable and barely maintainable code):

我已经编写了 $ original = $ compressed; ，并开始逐步逆转此表达式的右侧部分:

I've written the $original = $compressed; and started reversing the right part of this expression step by step:

1. 从base64解码为二进制字符串
2. 将其拆分为数组
3. 将每个字符转换为其ASCII码
4. 将十进制ASCII码转换为二进制
5. 将所有二进制数字合并为一个
6. 将长二进制字符串拆分为数组

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