Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Boolean searches

  1. Aug 22, 2003 #1
    in school we were only breifly introduced to the boolean system. we used it for google searches, putting minus sign when we didn't want the word to be included in the results. that was all we learned, but it helped a lot in narrowing searches. i just want to know what other sort of things like that are there?
  2. jcsd
  3. Aug 23, 2003 #2

    This is funny. I asked a friend
    the same question the other day
    because she is an internet whiz
    but it turned out she'd never
    bothered to learn.

    Finding your question here made
    me wonder again, and it suddenly
    occured to me, why not google up
    Boolean Search?

    Boolean Searching on the Internet
    Address:http://library.albany.edu/internet/boolean.html [Broken] Changed:11:13 AM on Saturday, August 23, 2003

    And here is your answer!

    Last edited by a moderator: May 1, 2017
  4. Aug 23, 2003 #3
    huh, thanks, i'd have never even thought of googling it...
  5. Aug 27, 2003 #4
    Each search engine has its own set of rules for Boolean, some allow more powerful searches than others.

    It is told here: http://www.pcworld.com/howto/article/0,aid,12286,00.asp [Broken]

    This link teaches how to maximize the Google experience:

    http://www.pcworld.com/howto/article/0,aid,110323,00.asp [Broken]
    Last edited by a moderator: May 1, 2017
  6. Sep 6, 2003 #5
    I dont know if your question was only intended for internet searches, but here is a bit more boolean info.
    Im still studying, so forgive me if my memory decieve me.
    Boolean algebra is a widely used technique in logical circuits, meaning your pc consists of thousands of AND & OR gates, which in all its simplicity compares 2 or more inputs, and outputs a result of either true or false. Your digital watch, calculator, pc, well all things that process data is build from these simple functions. Well, there are more to it than that, there is inverters, meaning if the intput is true, then the output is false and vice versa. There are of course timers and others fancy stuff, plus some specialized boolean functions like X-OR which is true when only one of the inputs are true, but it all comes down to boolean algebra.
    Since pcs, calculators and such things use binary numbers, being 1 and 0, it is quite tempting to use 1 as true and 0 as false... By using boolean algebra you can build advanced functions like adding, subtracting, multiply and division... ( / )
    This is a truely amazing and wide field, so Im gonna stop soon... But to illustrate that I'm right, check this out:
    To add 2 binary numbers, each 1 digit, this is the inputs and the outputs ( if its too confusing, use true or false instead... ):

    Input A Input B Result Carry out
    0 0 0 0
    0 1 1 0
    1 0 1 0
    1 1 0 1

    Carry out is in case the result is more that 1 which is maximum value for a binary number being only 1 or 0...
    So if A OR B is 1 the Result is 1 and Carry out is 0
    If A AND B is 1 the Result is 0 and Carry out is 1
    Acutally if you remember the X-OR gate as mentioned earlier, it would fit as the Result circuit as only 1 input must be 1 if output is true.
    For the Carry out an AND gate would fit nicely, only being true if both inputs are true.
    Now, I dont know if you can understand this, but think about it, if that AND & OR you write in google is the same kind of considerations used to run all digital things, the guys who invented the system dont really get enough credit, now do they? ( Considering the fact that all the advanced features there is ie. in your pc is build from these small and simple logical devices and simple boolean algebra )
    If you did understand it, try thinking about how to subtract, multiply and so forth, its very amusing.
    Well, enough from me for now... I hope you understood this and if any thing needs to be corrected please do so, I only wanted to indicate that boolean algebra is an extreemely wide and interesting branch of technology and logic.

    Best regards

    Thomas Hansen
  7. Sep 19, 2003 #6
    Try googling on 'regular expressions', or regexp. This is most powerful string manipulation and matching technique, that is also sometimes present in search engines. It combines boolean searches with pattern sequencing. Far more advanced than simple boolean searches. Its standard on unixes.

    If you want to know how search engines find stuff, perhaps search for 'binary tree' algoritms. There are few very good animated java applets to visualise it.
  8. Sep 21, 2003 #7
    You don't really need Boolean for Google. Google has an advance search system, which is basically boolean but easier to use.

    School Computer teachers are so ignorant sometimes. I've had computer teachers that don't have a clue what they are talking about.

    One computer teacher told me Bill Gates invented the mouse and that I was wrong. I found a document in an encyclopedia on the internet about computer history. I corrected her in front of the class and she started yelling at me and gave me a detention in front of everybody. Then she gave the technology award to someone else when I was the only one in the school who knew anything about computer science or programming.

    My former school librarian thought she was computer savvy, and she would make cracks about my computer knowledge even though she knew as much as a 10-year old would.

    I've learned to avoid taking computer classes at school and when librarians say they are computer literate, they are lying. LYING!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook