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Thanks, Peter. I don't speak Ruby. Uh, line 5 contains a small function definition, which is applied to each ...slice of the input string, is that right? Do

Thanks, Peter. I don't speak Ruby. Uh, line 5 contains a small function definition, which is applied to each ...slice of the input string, is that right? Do you (or anyone else) have time to describe this code in English or pseudocode? I'll start. Let there be a function called hash which takes a string named str and an integer named length_of_hash (which defaults to 20). Slice the string (str) into length_of_hash equally-sized pieces? Take numeric value of each character (of each slice??) and do.. something to it, something involving modulo 256, unless it's zero. Save all the results. Express each numeric result as hexidecimal and append all those together. Return it, probably. Clearly there are bugs in the translation. :)

petercooper 12y ago
In short, convert the input string into an array of its character values, group those values into sub-arrays of length 'x', add together the aligned values in each sub-array and modulo each by 256, output the resulting values in hex pairs joined together in a big string. Example, with a hash length of 4: "helloworld" => [104, 101, 108, 108, 111, 119, 111, 114, 108, 100] => [[104, 101, 108, 108], [111,119,111,114], [108, 100]] => [67, 64, 219, 222] => "4340dbde" So if one character is different in the string, only one hex value in the output will vary too. However, a flaw of the plan is that changes spaced out at an interval that matches your hash "length" will only affect one hex value in the output, but you run into the pigeonhole principle if you want a hash of limited size to have the same or similar Levenshtein distance as the potential inputs, but I suspect there are far smarter solutions :-)