For years, I am using a code that contains the following condition ref \$_[0] eq ‘SCALAR’ I always expect there an ARRAY or SCALAR, but recently I passed substr() into that parameter. Unexpected things happened. The condition returned a false value. Then I figured it out. The ref returned LVALUE instead of SCALAR. Since LVALUE… Read More How to check if LVALUE represents SCALAR

A simple simulation of the problem: use strict; use warnings; sub uniq { my %seen; grep !$seen{$_}++, @_; } my @a = (1, 2, 3, 1, 2); print shift @{uniq(@a)}; Can’t use string ("3") as an ARRAY ref while "strict refs" in use >Solution : Need to impose a list context on the function call,… Read More Get the first item of the list returned by function

I’m trying to do a match file name with a document with an if condition, but Perl doesn’t seems to catch it. I defined my document as: my $file = $filename Which $filename is equals to "/Desktop/src/file_top.sv". I’m running a program that reads the $filename and if the file is not named "file_top.sv", then the… Read More Why doesn't Perl recognize the file name?

I’m just starting to learn Perl, and I (accidentally) came across this print behavior I can’t explain. If I do: print "$("; the result I get is: 1000 4 20 24 25 27 29 30 44 46 117 1000 1001 Here’s a nice screenshot. Probably makes total sense for someone who knows Perl, so if… Read More Perl print "$("

I’m writing a program currently in Perl, and what I want it to do is take the user’s input (a string in my case), read a file, find an entry in the file with that input, and then print. This is what I have so far in this particular subroutine where this bit of code… Read More Reading from a File Based on a String Input

I have a set of files with sample data like the one below, I need to transform the data to put all the object files(followed by -o) in 1 column and linked libs(followed by -l) in 2nd column. This format is consistent in the entire make output. hello there -o one two three four -labc… Read More perl oneliner print the array and other match in same print statement

I feel like this is a simple problem. But I am stuck and to be honest my mind is having an info overload at the moment. I am also new to Perl and I’m still trying to explore it. So I have a variable that contains a string: $strings = "3A 1B 2A 5A 4B"… Read More How to sort an array of strings numerically?

I am facing a (naive) problem with regular expression. I need to find any substrings composed of a fixed number (n) of different characters. So, for "aaabcddd", if n=3 the substrings that I expect to find are: "abc" and "bcd". My idea is to use n-1 capture groups and ‘[^’ to exclude characters already matched.… Read More Regex to match substrings containing n non repeted characters

i want to add a newline to the lastest element of an array i have tried this : $array[-1] .= "\n"; but it doesn’t work and i get the following error message : Modification of non-creatable array value attempted, subscript -1 i have tried a few other methods as well (without .=), without success. should… Read More Append last array element in Perl

I’m trying to write a sort function in Perl. I need that "name_iwant_last" will be the last in sorted hash. My code: %libs = ( "00000000000","00000000000", "aaaaaaaaaaa","aaaaaaaaaaa", "AAAAAAAAAA","AAAAAAAAAA", "name_iwant_last","name_iwant_last", "zzzzzzzzzzzzz","zzzzzzzzzzzzz", "ZZZZZZZZZZZ","ZZZZZZZZZZZ", "9999999999","9999999999" ); sub lib_sort { #print "cosa ordino "; #print $libs{$a}; #print $libs{$b}; #print "\n"; return 1 if (index($libs{$a} , "name_iwant_last") != -1); return… Read More sort function in Perl – random output