如何使用Excel / VBA将字符串压缩/解压缩为32个字符的字母数字字符串？

Question

I hope I'm asking the right question, but if not I'd like to clarify what I'm trying to do.

I'd like to take a string of alphabetic text and convert it into a 32-character alphanumeric string of text. I would then like to covert that 32-character alphanumeric string of text back to the original text. I only care about shortening the length. I don't care about security. I don't care about maintaining the case sensitivity of the original string.

Is something like this even possible or am I trying to create bytes of data out of thin air?

Answer 1

In base 62 (62 different characters), a string of 32 characters can represent 62^32 different values, which comes out to about 3.7922554e+57.

An arbitrary string in your origin alphabet of 28 characters (AZ plus space and period) of length 39 could be any of 2.7489271e+56 different patters. If the length is increased to 40 characters, there are 7.6969959e+57 different patterns.

What this means: The theoretical maximum length arbitrary string you could store is 39 characters. In practice, it would almost certainly be less than that. Note that the example string you provided in the comments is 55 characters long.

This is for an arbitrary string. Compression algorithms often look for patterns that can be compressed further. But that depends on the nature of the string being compressed.