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> From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of > Eric Lease Morgan > Sent: Friday, May 28, 2010 09:35 AM > To: [log in to unmask] > Subject: [CODE4LIB] generating unique integers > > Given a list of unique strings, how can I generate a list of short, > unique integers? > > I have a list of about 250 unique author/title combinations, such as: > > Aeschylus / Prometheus Bound > Aeschylus / Suppliant Maidens > American State / Articles of confederation > American State / Declaration of Independence > Aquinas / Summa Theologica > Aristophanes / Achamians > Aristophanes / Clouds > Aristophanes / Ecclesiazusae > Aristotle / On Generation And Corruption > Aristotle / On The Gait Of Animals > Aristotle / On The Generation Of Animals > ... > > From each author/title combination I want to create a file name (key). > Specifically, I want a file name with the following form: author- > firstwordofthetitle-integer.txt Such a scheme will make it > (relatively) easy for me to look at the file name and know the what > title is and by whom. > > Using Perl, how can I convert the author/title combination into some > sort of integer, checksum, or unique value that is the same every time > I run my script? I don't want to have to remember what was used before > because I don't want to maintain a list of previously used keys. Should > I use some form of the pack function? Should I sum the ASCII values of > each character in the author/title combination? You could MD5 hash the author/title combination which would give you the same hash so long they were the author/title combination was the same, e.g., letter case and spelling, etc. However, that doesn't meet your requirement of an small integer, but if you are using the value for a Perl hash it might not matter all that much. Andy.