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I am after some help trying to convert the following log I have to plain text.
This is a URL so there maybe %20 = 'space' and other but the main bit I am trying convert is the char(1,2,3,4,5,6) to text.
Below is an example of what I am trying to convert.
select%20char(45,120,49,45,81,45),char(45,120,50,45,81,45),char(45,120,51,45,81,45)
What I have tried so far is the following while trying to added into the char(in here) to convert with the chr($2)
perl -pe "s/(char())/chr($2)/ge"
All this has manage to do is remove the char but now I am trying to convert the number to text and remove the commas and brackets.
I maybe way off with how I am doing as I am fairly new to to perl.
perl -pe "s/word to remove/word to change it to/ge"
"s/(char(what goes in here))/chr($2)/ge"
Output try to achieve is
select -x1-Q-,-x2-Q-,-x3-Q-
Or
select%20-x1-Q-,-x2-Q-,-x3-Q-
Thanks for any help
There's too much to do here for a reasonable one-liner. Also, a script is easier to adjust later
use warnings;
use strict;
use feature 'say';
use URI::Escape 'uri_unescape';
my $string = q{select%20}
. q{char(45,120,49,45,81,45),char(45,120,50,45,81,45),}
. q{char(45,120,51,45,81,45)};
my $new_string = uri_unescape($string); # convert %20 and such
my #parts = $new_string =~ /(.*?)(char.*)/;
$parts[1] = join ',', map { chr( (/([0-9]+)/)[0] ) } split /,/, $parts[1];
$new_string = join '', #parts;
say $new_string;
this prints
select -x1-Q-,-x2-Q-,-x3-Q-
Comments
Module URI::Escape is used to convert percent-encoded characters, per RFC 3986
It is unspecified whether anything can follow the part with char(...)s, and what that might be. If there can be more after last char(...) adjust the splitting into #parts, or clarify
In the part with char(...)s only the numbers are needed, what regex in map uses
If you are going to use regex you should read up on it. See
perlretut, a tutorial
perlrequick, a quick-start introduction
perlre, the full account of syntax
perlreref, a quick reference (its See Also section is useful on its own)
Alright, this is going to be a messy "one-liner". Assuming your text is in a variable called $text.
$text =~ s{char\( ( (?: (?:\d+,)* \d+ )? ) \)}{
my #arr = split /,/, $1;
my $temp = join('', map { chr($_) } #arr);
$temp =~ s/^|$/"/g;
$temp
}xeg;
The regular expression matches char(, followed by a comma-separated list of sequences of digits, followed by ). We capture the digits in capture group $1. In the substitution, we split $1 on the comma (since chr only works on one character, not a whole list of them). Then we map chr over each number and concatenate the result into a string. The next line simply puts quotation marks at the start and end of the string (presumably you want the output quoted) and then returns the new string.
Input:
select%20char(45,120,49,45,81,45),char(45,120,50,45,81,45),char(45,120,51,45,81,45)
Output:
select%20"-x1-Q-","-x2-Q-","-x3-Q-"
If you want to replace the % escape sequences as well, I suggest doing that in a separate line. Trying to integrate both substitutions into one statement is going to get very hairy.
This will do as you ask. It performs the decoding in two stages: first the URI-encoding is decoded using chr hex $1, and then each char() function is translated to the string corresponding to the character equivalents of its decimal parameters
use strict;
use warnings 'all';
use feature 'say';
my $s = 'select%20char(45,120,49,45,81,45),char(45,120,50,45,81,45),char(45,120,51,45,81,45)';
$s =~ s/%(\d+)/ chr hex $1 /eg;
$s =~ s{ char \s* \( ( [^()]+ ) \) }{ join '', map chr, $1 =~ /\d+/g }xge;
say $s;
output
select -x1-Q-,-x2-Q-,-x3-Q-
How can I print a string (single-quoted) containing double-backslash \\ characters as is without making Perl somehow interpolating it to single-slash \? I don't want to alter the string by adding more escape characters also.
my $string1 = 'a\\\b';
print $string1; #prints 'a\b'
my $string1 = 'a\\\\b';
#I know I can alter the string to escape each backslash
#but I want to keep string as is.
print $string1; #prints 'a\\b'
#I can also use single-quoted here document
#but unfortunately this would make my code syntactically look horrible.
my $string1 = <<'EOF';
a\\b
EOF
print $string1; #prints a\\b, with newline that could be removed with chomp
The only quoting construct in Perl that doesn't interpret backslashes at all is the single-quoted here document:
my $string1 = <<'EOF';
a\\\b
EOF
print $string1; # Prints a\\\b, with newline
Because here-docs are line-based, it's unavoidable that you will get a newline at the end of your string, but you can remove it with chomp.
Other techniques are simply to live with it and backslash your strings correctly (for small amounts of data), or to put them in a __DATA__ section or an external file (for large amounts of data).
If you are mildly crazy, and like the idea of using experimental software that mucks about with perl's internals to improve the aesthetics of your code, you can use the Syntax::Keyword::RawQuote module, on CPAN since this morning.
use syntax 'raw_quote';
my $string1 = r'a\\\b';
print $string1; # prints 'a\\\b'
Thanks to #melpomene for the inspiration.
Since the backslash interpolation happens in string literals, perhaps you could declare your literals using some other arbitrary symbol, then substitute them for something else later.
my $string = 'a!!!b';
$string =~ s{!}{\\}g;
print $string; #prints 'a\\\b'
Of course it doesn't have to be !, any symbol that does not conflict with a normal character in the string will do. You said you need to make a number of strings, so you could put the substitution in a function
sub bs {
$_[0] =~ s{!}{\\}gr
}
my $string = 'a!!!b';
print bs($string); #prints 'a\\\b'
P.S.
That function uses the non-destructive substitution modifier /r introduced in v5.14. If you are using an older version, then the function would need to be written like this
sub bs {
$_[0] =~ s{!}{\\}g;
return $_[0];
}
Or if you like something more readable
sub bs {
my $str = shift;
$str =~ s{!}{\\}g;
return $str;
}
I want to get the split characters. I tried the below coding, but I can able to get the splitted text only. However if the split characters are same then it should be returned as that single characters
For example if the string is "asa,agas,asa" then only , should be returned.
So in the below case I should get as "| : ;" (joined with space)
use strict;
use warnings;
my $str = "Welcome|a:g;v";
my #value = split /[,;:.%|]/, $str;
foreach my $final (#value) {
print $final, "\n";
}
split splits a string into elements when given what separates those elements, so split is not what you want. Instead, use:
my #punctuations = $str =~ /([,;:.%|])/g;
So you want to get the opposite of split
try:
my #value=split /[^,;:.%|]+/,$str;
It will split on anything but the delimiters you set.
Correction after commnets:
my #value=split /[^,;:.%|]+/,$str;
shift #value;
this works fine, and gives unique answers
#value = ();
foreach(split('',",;:.%|")) { push #value,$_ if $str=~/$_/; }
To extract all the separators only once, you need something more elaborate
my #punctuations = keys %{{ map { $_ => 1 } $str =~ /[,;:.%|]/g }};
Sounds like you call "split characters" what the rest of us call "delimiters" -- if so, the POSIX character class [:punct:] might prove valuable.
OTOH, if you have a defined list of delimiters, and all you want to do is list the ones present in the string, it's much more efficient to use m// rather than split.
my code is as follows
my $string = $cells[71];
print $string;
this prints the string but where spaces should be there is a box with 01 10 in it. I opened it in Notepad++ and the box turned into a black GS (which i am assuming is group separator).
I looked online and it said to use:
s/[^[:print:]]+//g
but when i set the string to:
my $string =~s/[^[:print:]]+//g
and I run the program i get:
4294967295
How do i resolve this?
I did what HOBBS said and it worked... thanks :)
Is there anyway I could print an enter where each of these characters are ( the box with 1001)?
When doing a regex match, you need to be careful to write $var =~ /pattern/, not $var = ~ /pattern/. When you use the second one, you're doing /pattern/, which is a regex match against $_, returning a number in scalar context. Then you do ~, which takes the bitwise inverse of that number, then ($var =) you assign that result to $var. Not what you wanted at all.
You have to assign the variable first, then do the substitution:
my $string = $cells[71];
$string =~ s/[^[:print:]]+//g;
I have a Perl application that takes from command line an input as:
application --fields 1-6,8
I am required to display the fields as requested by the user on command line.
I thought of substituting '-' with '..' so that I can store them in array e.g.
$str = "1..15,16" ;
#arr2 = ( $str ) ;
#arr = ( 1..15,16 ) ;
print "#arr\n" ;
print "#arr2\n" ;
The problem here is that #arr works fine ( as it should ) but in #arr2 the entire string is not expanded as array elements.
I have tried using escape sequences but no luck.
Can it be done this way?
If this is user input, don't use string eval on it if you have any security concerns at all.
Try using Number::Range instead:
use Number::Range;
$str = "1..15,16" ;
#arr2 = Number::Range->new( $str )->range;
print for #arr2;
To avoid dying on an invalid range, do:
eval { #arr2 = Number::Range->new( $str )->range; 1 } or your_error_handling
There's also Set::IntSpan, which uses - instead of ..:
use Set::IntSpan;
$str = "1-15,16";
#arr2 = Set::IntSpan->new( $str )->elements;
but it requires the ranges to be in order and non-overlapping (it was written for use on .newsrc files, if anyone remembers what those are). It also allows infinite ranges (where the string starts -number or ends number-), which the elements method will croak on.
You're thinking of #arr2 = eval($str);
Since you're taking input and evaluating that, you need to be careful.
You should probably #arr2 = eval($str) if ($str =~ m/^[0-9.,]+$/)
P.S. I didn't know about the Number::Range package, but it's awesome. Number::Range ftw.
I had the same problem in dealing with the output of Bit::Vector::to_Enum. I solved it by doing:
$range_string =~ s/\b(\d+)-(\d+)\b/expand_range($1,$2)/eg;
then also in my file:
sub expand_range
{
return join(",",($_[0] .. $_[1]));
}
So "1,3,5-7,9,12-15" turns into "1,3,5,6,7,9,12,13,14,15".
I tried really hard to put that expansion in the 2nd part of the s/// so I wouldn't need that extra function, but I couldn't get it to work. I like this because while Number::Range would work, this way I don't have to pull in another module for something that should be trivial.
#arr2 = ( eval $str ) ;
Works, though of course you have to be very careful with eval().
You could use eval:
$str = "1..15,16" ;
#arr2 = ( eval $str ) ;
#arr = ( 1..15,16 ) ;
print "#arr\n" ;
print "#arr2\n" ;
Although if this is user input, you'll probably want to do some validation on the input string first, to make sure they haven't input anything dodgy.
Use split:
#parts = split(/\,/, $fields);
print $parts[0];
1-6
print $parts[1];
8
You can't just put a string containing ',' in an array, and expect it to turn to elements (except if you use some Perl black magic, but we won't go into that here)
But Regex and split are your friends.