String interpolation in perl

Question

I am new to perl, I am learning using O'reillys Learning Perl book. Unicode characters(as written in the book) like this ♠ can be printed using print "\x{2668}". I was using foreach loop to print a range of Unicode characters.

Example: from 2660 - 2670;

I have written the following code,

foreach $num (2660..2670)
{
        print "Character for $num  is:","\x{$num} \n";

}

Which was giving the following output,

Illegal hexadecimal digit '$' ignored at ./Printing_messages.pl line 10.
Character for 2660  is: 
Character for 2661  is: 
Character for 2662  is: 
Character for 2663  is: 
Character for 2664  is: 
Character for 2665  is: 
Character for 2666  is: 
Character for 2667  is: 
Character for 2668  is: 
Character for 2669  is: 
Character for 2670  is:

After that I've made some other tweaks, but nothing worked. What is the problem with the my program ? I don't understand. Is there how to make it work ?

ikegami · Accepted Answer · 2012-12-21 09:27:56Z

4

You want

print "Character for $num is: ", chr($num), "\n";

answered Dec 21, 2012 at 9:27

ikegami

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Orabîg · Accepted Answer · 2012-12-21 07:52:05Z

-3

You can write something like :

foreach $num (2660..2670)
{
        print "Character for $num  is:",eval(qq!\"\\x{$num} \\n\"!);
}

The problem with your original program, is that perl cannot evaluate "\x{...}" because this evaluation is done before the interpolation of $num.

answered Dec 21, 2012 at 7:52

Orabîg

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4 Comments

aravind ramesh Over a year ago

Its Working. Thank you. is eval a function ?

ikegami Over a year ago

Generating a Perl program, compiling it and running it is severe overkill.

LeoNerd Over a year ago

Using eval() for this is seriously bad form. Consider the chr() function instead, as the other answer shows.

Orabîg Over a year ago

This program was for educative usage only. I was answering to the "I am learning..." thing. Of course char is a better solution, but his program was not meant to be production quality... I thought he was trying to use the \x{} syntax...

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