Assuming the perl code is something like this...
open(STDOUT, ">$PName") || die "Can't redirect stdout";
$status = system("python Example.py $PName.txt");
(That is taken from http://www.linuxquestions.org/questions/programming-9/perl-script-call-python-linux-551063/)
What do I have to do in python to be able to pass a string to the perl script?
Would I need to simply return the string? or print to console? or something else?
You could just print to console, and in perl use:
my $from_py = `python foo.py bar`;
The system command is not useful in Perl for capturing output of a command. You should use backticks to execute a command and write to stdout in the Python script.
#-- returns one string
$result = `command arg1 arg2`;
#-- returns a list of strings
@result = `command arg2 arg2`;
See the linked source below for more information.
The simplest way is to use backticks (``) as in
my $output = `python Example.py $PName.txt`;
print "Backticks:\n", $output;
A synonymous approach involves qx//.
my $output = qx/python Example.py $PName.txt/;
print "Backticks:\n", $output;
To read each line, open a pipe from the Python subprocess.
print "Pipe:\n";
open my $fh, "python Example.py $PName.txt |";
while (<$fh>) {
print "Perl got: ", $_;
}
close $fh or warn "$0: close: $!";
As outlined in the “Safe Pipe Opens” section of the perlipc documentation, you can bypass the shell by splitting the command into arguments.
open my $fh, "-|", "python", "Example.py", "$PName.txt";
Output:
Backticks: Python program: Example.py Argument: pname-value.txt Pipe: Perl got: Python program: Example.py Perl got: Argument: pname-value.txt
