fig05_04.pl

来自「PERL语言资料 可以用于PERL程序设计」· PL 代码 · 共 45 行

#!/usr/bin/perl
# Fig. 5.4: fig05_04.pl
# Demonstrating map and grep.

@numbers = ( 1 .. 10 );
print "\@numbers: @numbers\n\n";

# locate all numbers less than 6
foreach ( @numbers ) {
   push( @smallNumbers, $_ ) if $_ < 6;
}

print "Numbers less than 6:\n", 
      "foreach: @smallNumbers\n";

@smallNumbers2 = grep( $_ < 6, @numbers );
print "grep:    @smallNumbers2\n\n";

# multiply every number by 2
foreach ( @numbers ) {
   push( @doubledNumbers, $_ * 2 );
}

print "Double each number:\n",
      "foreach: @doubledNumbers\n";

@doubledNumbers2 = map( $_ * 2, @numbers );
print "map:     @doubledNumbers2\n";

###########################################################################
#  (C) Copyright 2001 by Deitel & Associates, Inc. and Prentice Hall.     #
#  All Rights Reserved.                                                   #
#                                                                         #
#  DISCLAIMER: The authors and publisher of this book have used their     #
#  best efforts in preparing the book. These efforts include the          #
#  development, research, and testing of the theories and programs        #
#  to determine their effectiveness. The authors and publisher make       #
#  no warranty of any kind, expressed or implied, with regard to these    #
#  programs or to the documentation contained in these books. The authors #
#  and publisher shall not be liable in any event for incidental or       #
#  consequential damages in connection with, or arising out of, the       #
#  furnishing, performance, or use of these programs.                     #
###########################################################################