what are boolean operators?

17
What are Boolean Operators? Mrs. Mersand December 2007

Upload: isra

Post on 10-Jan-2016

41 views

Category:

Documents


1 download

DESCRIPTION

What are Boolean Operators?. Mrs. Mersand December 2007. Boolean operators are named after George Boole, an Englishman, who invented them as part of a system of logic in the mid-1800's. The most common Boolean operators are AND, OR, NOT and NEAR, additionally, () can be used - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: What are Boolean Operators?

What are Boolean Operators?

Mrs. Mersand

December 2007

Page 2: What are Boolean Operators?

Boolean operators are named after George Boole, an Englishman, who invented them as part of a system of logic in the mid-1800's. The most common Boolean

operators are AND, OR, NOT and NEAR, additionally, () can be used

They are used to combine search terms when doing research

In math, they are used to connect logical statements

Page 3: What are Boolean Operators?

No…they aren’t leaning

ghosts….

Page 4: What are Boolean Operators?

And

Would everybody wearing Jeans, please stand up # _____

Would everybody wearing Sneakers please stand up # _____

Would everybody wearing jeans and sneakers please stand up # _____

Page 5: What are Boolean Operators?

Venn Diagram of AND

Jeans Sneakers

Page 6: What are Boolean Operators?

AND Explained

Using the operator AND between keywords will limit the results of a search because all the keywords have to be present in order for an item to be retrieved.

Page 7: What are Boolean Operators?

OR

Would everybody wearing jeans please stand up #______

Would everybody wearing sneakers please stand up #______

Would everybody wearing jeans OR sneakers please stand up #______

Page 8: What are Boolean Operators?

Venn Diagram of OR

Jeans Sneakers

Page 9: What are Boolean Operators?

OR Explained

Using the OR operator results in either or both of your search terms appearing in your results.

Using the OR operator will result in a larger number of retrieved items and therefore expands the search.

Page 10: What are Boolean Operators?

NOT

The NOT (or AND NOT) operator forbids the word after it from appearing in the items resulting from your search.

Would everybody wearing Jeans but NOT sneakers, please stand up

Page 11: What are Boolean Operators?

Venn Diagram for NOT

Jeans Sneakers

Page 12: What are Boolean Operators?

NOT Explained

Not helps to limit your search because it takes out a category of undesirable results.

NOT or AND NOT thus narrows or limits a search by excluding the keyword immediately following it.

Page 13: What are Boolean Operators?

NEAR

Finds the terms within 10 words of each other

Domestic NEAR Violence would make sure these two words

appeared close enough to each other that they would be referring to domestic violence

Page 14: What are Boolean Operators?

( )

Used to group together words or phrases, for example

(domestic NEAR violence) and (police AND trial)

Brings could be used to search for domestic violence that has been interrupted by the police or gone to trial

Page 15: What are Boolean Operators?

Order of operators

Just as in math, certain operators are done first. The order for Boolean operators is:( )NEARNOTANDOR

Page 16: What are Boolean Operators?

Be sure to use proper search structure

What would the following search bring up?

Dogs AND ((rabies OR rabid) NOT (domestic OR Pet) )

The search will look for the words rabies and rabid Then domestic and pet Then remove all results that contain the words

domestic or pet from the results Then remove anything that does not contain the word

dog from the results

Page 17: What are Boolean Operators?

Now lets try some on our own

You should always use more than one search engine when you are doing research

Try thinking out of the box, give Google a break!!

Other options

infomine.ucr.eduwww.lii.orgwww.ipl.orgwww.nettrekker.comwww.altavista.com

www.mama.comwww.dogpile.comwww.yahoo.comwww.surfwax.comwww.ixquick.com