Searching Web Sites

Simple Searching

• Searching can be performed in Perl using the grep ( ) function
• Syntax

grep (/EXPRESSION/, ARRAY);

selects any elements from ARRAY for which EXPRESSION is true

grep ( ) returns a subarray or ARRAY's elements

• Example

    @autos = qw(FordMustang, FordPinto,

                FordTiempo, DodgeDart,

                DodgeVolare, ChevyCamaro,

                ChevyMalibu) ;

    @fords = grep(/Ford/, @autos);

    print @fords;

• The grep ( ) function is case sensitive
• To tell grep to ignore case, use the I switch
• Syntax

grep (/EXPRESSION/i, ARRAY);

• Example

    @autos = qw(FordMustang, FordPinto,

                FordTiempo, DodgeDart,

                DodgeVolare, ChevyCamaro,

                ChevyMalibu) ;

    @fords = grep(/ford/i, @autos);

    print @fords;

• Example - Searching a file

    

    open (auto_file, "autos.txt") ||

          die ("Can't open Autos file: $!\n");

    @autos = <auto_file>;

    close (auto_file);

 

    @results = grep(/$srch_arg/i,@autos);

The grep ( ) function also returns the number of items found in the subarray name

• Example:

     parse_input (*fields);

     $srch_arg = $fields{'car_name'};

 

     @results = grep(/$srch_arg/i,@autos);

 

     if ($#results > 0){

         do something;

 

     }