Examples of Advanced Description Searches

Below we give many of the advanced search options available with the two fields description and comment.  The example I give are all aimed at the description field, but apply to either.  The key thing to note is that matches need only match part of the string--so a search using just 2 in the description field will match a prime with a 2 anywhere in its description.

An expression may begin with the word NOT (uppercase) to negate a search

Example:  NOT [2345] will match the primes without the digits 2, 3, 4 or 5 in their descriptions

Example:  NOT .^ will match primes without the exponentiation operator

An expression may contain the word OR (uppercase) to allow a boolean search

Example:  3^ OR 5^ will match the primes like Phi(3,-163195^8192) and 343372*3^178255-1

Example:  2^ OR 3^ OR 5^ will return mostly primes like 3*2^478785+1 (which greatly outnumber the previous types)

An expression may begin with the character ^ (carat) which will only match at the beginning of the prime description.  (Using ^ anywhere else in the description field will simply match the exponentiation operator.)

Example:  ^2 will match prime descriptions that begin with the digit 2.
Example:  .^2 will match prime descriptions that have an exponent that begins with the digit 2.

An expression may end with the character $ (dollar sign) which will only match at the end of the prime description. 

Example:  2$ will match prime descriptions that end with the digit 2.
Example:  $2 can not match any prime (how can 2 occur after the end?)

The character . (period) will match any single character

Example:  (..) will match primes with two characters in a pair of parenthesis (e.g., 43013#*R(23)^11+1)
Example:  .. will match everything on the list (as there are no one-character descriptions)
Example:  ^......$ will match every description with exactly six-characters.
Example:  ^.?3 will match description whose first or second character is 3.  (The couplet .? matches any 0 or 1 characters).

The character % (percent sign) will match any (0 or more) characters.

Example:  ^2%1$ will match descriptions beginning with the digit 2 and ending with the digit 1 (with anything else in between)
Example:  % will match everything on the list.

Many, GRE constructs will work.  The fact that +, *, ( and ) are quoted (to make searching for algebraic expressions easy) eliminates many, but you can get around this by being creative and using the fact MySQL represents many GRE expressions using [, ], {, }, and :. 

Example: ^[123]{3,}[[:digit:]]{3,}* will match those beginning with at least three digits from the set {1,2,3} followed by at least three more digits (0 through 9).
Example: ^[[:alpha:]]{1,2}( will match those beginning with one or two letters followed by a parenthesis.

Internally % is translated to the GRE '.*'.