Ansys_120_CFX_官方教程.pptVIP

Handles can also be external apps Perl can launch and interact with external processes System() spawns an external process and waits for it to finish Can open a command as a handle, and interact via STDIN. Command is executed when handle is closed. $logfile = “logfile.dat”; system(“grep -i error $logfile errors.dat”); open(SOLVER,|cfx5solve -def $myRun); close(SOLVER); #waits until done to continue External Processes Perl can use regular expressions for general text pattern matching and replacement Complex and ugly, but powerful print “Any last requests? ”; chomp($a = STDIN); if ($a =~ /^y/i) { # does the input begin with y print “What is it?”; STDIN; print “Sorry, I can’t do that.\n”; } print “Ready, aim, Fire !\n”; $string = “foot fool buffoon”; $string =~ s/foo/bar/g; # string is now “bart barl bufbarn” $line = “X,Y,Z,1,,1.234,34”; @fields = split(/\,/, $line); # @fields is (“X”,”Y”,”Z”,”1”,””,”1.234”,”34”) Regular Expressions Subroutines are just user defined functions. Declared with ‘sub’ Subroutines return one or more values from a return statement … or the value of the last statement if no explicit return. Invoked by calling subName(args) sub subName { statement 1; statement 2; [...] } $result = doSomething($a,$b); Subroutines Arguments are passed to a subroutine using the @_ list Must pass lists and arrays by reference sub addThreeNumbers { ($a, $b, $c) = @_; $result = $a + $b + $c; return $result; } Subroutines Use ‘\’ in front of a variable to create a scalar reference (pointer) $listRef = \@myList; De-reference by using a variable reference type ($, @ or %) push(@$listRef,”new Value”); Directly access elements in a reference using - notation For arrays: $listRef-[$index] For hashes: $hashRef-{$key} References sub printHash { ($hashRef) = @_; foreach $key (keys(%$hashRef)) { print “Key: $key, Value: “ . $hashRef-{$key} . “\n”; } } %myHash = (“a” = “b”, “c” = “d”); printHash(\%myHash); By def