CODEWITHSUNDEEP
perl
jackd
jackd

Reputation: 357

Perl, how to print evaluation of sum of numbers using "print"

Look at the following code sample.

$ct=5;
print "hey $ct+1";

When evaluated, this returns:

hey 5+1

However, I'm trying to get the code to return:

hey 6

Does anybody know if there is some sort of evaluation call that I can make to have this occur correctly, or a way to change the syntax a tad? I know I could simply do:

$dum=$ct+1;
print "hey $dum";

But what I'm showing you is a simple version of something more complicated. If I could get this small example to work correctly, my larger problem is solved. Thanks.

Upvotes: 3

Views: 13019

Answers (3)

squiguy
squiguy

Reputation: 33360

Another alternative is formatted printing. 

my $ct = 5;
printf "hey %s", $ct+1;

Upvotes: 8

mob
mob

Reputation: 118595

This is kind of intermediate Perl, but you can put your expression into a reference and dereference it inside double quotes:

print "hey @{[$ct+1]}";
print "hey ${\($ct+1)}";

Code like this is harder to read and gives Perl the reputation of being unfriendly to newbies, so I don't recommend it over extracting the expressions out of the quotes:

print "hey ", ($ct+1);
print "hey " . ($ct+1);

Upvotes: 2

ikegami
ikegami

Reputation: 385546

You want to execute a Perl addition operator, but the code only features a Perl string literal. You want

print "hey ", $ct+1;

If you did have Perl source code in a variable and you wanted to execute it, you'd have to invoke the Perl parser and compiler: eval EXPR.

Upvotes: 9

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