I'm currently using the Print When Expression function on my fields and whenever a field is getting excluded because of the print when condition it is leaving a blank space instead of just skipping it and moving on to the next one. Here is a picture showing what is happening:
So I'm trying to find a way to ignore that line break and keep the entire list uniform.
Here is my Print When Expression condition (which may or may not help you in answering my question): $F{clicks} < 1
Apply the Print When expression to the whole band, not to the fields.
Related
I'm trying to write a perl script to process a log4net log file. The fields in the log file are separated by a semi-colon. My end goal is to capture each field and populate a mysql table.
Usually I have lines that look a little like this (all on a single line)
DEBUG;2017-06-13T03:56:38,316-05:00;2017-06-13 08:56:38,316;79ab0b95-7f58-
44a8-a2c6-1f8feba1d72d;(null);WorkerStartup 1;"Starting services."
These are easy to process. I can simply split by semicolon to get the information I need.
However occassionally the "message" field at the end may span several lines, especially if there is a stack trace. I would want to capture the entire message as a single column. I cannot use split by semicolon, because the next lines would typically look like:
at some.random.classname
at another.classname
...
Can someone give some tips how to solve this problem?
The following solution uses that the number of " in a field is even ($p=~y/"//%2), this condition number of " odd may be changed by other that can indicate the field is not complete.
The number of columns splitted is fixed to 7 (to allow ; in last field) and may be changed for example #array = map {s/;$//} $p=~/\G(?:"[^"]*"|[^;])*;/g;.
The file is read line by line but a line is processed sub process when it's complete $p variable to store the previous line the last line is processed in END block.
perl -ne '
sub process {
#array = split /;/,$p,7;
# do something with array
print ((join "\n---\n", #array),"\n");
}
if ($p=~y/"//%2) {
$p.=$_;
next;
}
process;
$p=$_;
END{process}
' < logfile.txt
I am trying to select the below value from database:
Reporting that one of #its many problems had been the recent# extended
sales slump in women's apparel, the seven-store retailer said it would
start a three-month liquidation sale in all of its stores.~(A) its
many problems had been the recent~(B) its many problems has been the
recently~(C) its many problems is the recently~(D) their many problems
is the recent~(E) their many problems had been the recent~
i am selecting this value in variable $ques and then selecting a text as below:
$ques=~s/^(.*?)\#(.*?)\#(.*?)$/$2/;
Now, while replacing the ~ character in the string by
$3=~s/~/\n/g; ---->line 171
and running the script, I am getting one error as:
Modification of a read-only value attempted at main.pl line 171
I want to replace all the ~ character with '\n' and print the final value. Please suggest how to do it.
*I have researched this on net, but got confused that how to handle these read only variables.
You've already got a good explanation of the problem from José Castro. But there's another solution if you're using a recent-ish version of Perl (Update: having checked more carefully, I find that means 5.14+). The /r argument to the substitution operator will copy your string, make the substitution on the copy and then return that altered value.
So you could write:
my $new_value = $3 =~ s/~/\n/rg;
It sounds like what you really want in this case is split rather than regular expression capture groups:
my #parts = split(/#/, $ques);
$parts[2] =~ s/~/\n/g;
It makes the intent of your code clearer since you are, in fact, splitting on # symbols.
Just like you say, the special variables $1, $2, etc., are read-only, and that means that you can't perform that substitution on them.
Performing the substitution on $ques will do what you need:
$ques =~ s/~/\n/g;
print $ques;
Do note that in the earlier substitution that you're performing on $ques you're getting rid of all the ~ characters.
In if condition I used to take one value from log file after matching the particular pattern. That pattern is matched two times in log file. While matching the pattern first time that value is 0 and second time value is 48. It may be also reverse. First value may contain 48 and second value may contain 0. I need to calculate the exact value. So I planned to add these two values. but after adding these two values also while printing the total value in if condition I used to get the two values separately. But I need single value only.
Please give me solution to solve this issue.
Thanks in advance.
Do you mean something like this:
my $entry = "First is 10, seconds is 48";
if(my ($a,$b) = $entry =~ /(\d+)/g) {
print $a + $b,"\n"; # 58
}
But without actual code it is hard to see what your problem really is.
I am using Net::Whois::Raw to query a list of domains from a text file and then parse through this to output relevant information for each domain.
It was all going well until I hit Nominet results as the information I require is never on the same line as that which I am pattern matching.
For instance:
Name servers:
ns.mistral.co.uk 195.184.229.229
So what I need to do is pattern match for "Name servers:" and then display the next line or lines but I just can't manage it.
I have read through all of the answers on here but they either don't seem to work in my case or confuse me even further as I am a simple bear.
The code I am using is as follows:
while ($record = <DOMAINS>) {
$domaininfo = whois($record);
if ($domaininfo=~ m/Name servers:(.*?)\n/){
print "Nameserver: $1\n";
}
}
I have tried an example of Stackoverflow where
<DOMAINS>;
will take the next line but this didn't work for me and I assume it is because we have already read the contents of this into $domaininfo.
EDIT: Forgot to say thanks!
how rude.
So, the $domaininfo string contains your domain?
What you probably need is the m parameter at the end of your regular expression. This treats your string as a multilined string (which is what it is). Then, you can match on the \n character. This works for me:
my $domaininfo =<<DATA;
Name servers:
ns.mistral.co.uk 195.184.229.229
DATA
$domaininfo =~ m/Name servers:\n(\S+)\s+(\S+)/m;
print "Server name = $1\n";
print "IP Address = $2\n";
Now, I can match the \n at the end of the Name servers: line and capture the name and IP address which is on the next line.
This might have to be munged a bit to get it to work in your situation.
This is half a question and perhaps half an answer (the question's in here as I am not yet allowed to write comments...). Okay, here we go:
Name servers:
ns.mistral.co.uk 195.184.229.229
Is this what an entry in the file you're parsing looks like? What will follow immediately afterwards - more domain names and IP addresses? And will there be blank lines in between?
Anyway, I think your problem may (in part?) be related to your reading the file line by line. Once you get to the IP address line, the info about 'Name servers:' having been present will be gone. Multiline matching will not help if you're looking at your file line by line. Thus I'd recommend switching to paragraph mode:
{
local $/ = ''; # one paragraph instead of one line constitutes a record
while ($record = <DOMAINS>) {
# $record will now contain all consecutive lines that were NOT separated
# by blank lines; once there are >= 1 blank lines $record will have a
# new value
# do stuff, e.g. pattern matching
}
}
But then you said
I have tried an example of Stackoverflow where
<DOMAINS>;
will take the next line but this didn't work for me and I assume it is because we have already read the contents of this into $domaininfo.
so maybe you've already tried what I have just suggested? An alternative would be to just add another variable ($indicator or whatever) which you'll set to 1 once 'Name servers:' has been read, and as long as it's equal to 1 all following lines will be treated as containing the data you need. Whether this is feasible, however, depends on you always knowing what else your data file contains.
I hope something in here has been helpful to you. If there are any questions, please ask :)
I have a string like this <name>sekar</name>. I want to split this string (i am using perl) and take out only sekar, and push it into an array while leaving other stuff.
I know how to push into an array, but struck with the splitting part.
Does any one have any idea of doing this?
push #output, $1 if m|<name>(\w*)</name>|;
Try this:
my($name) = $string =~ m|<name>(.*)</name>|;
From perldoc perlop:
If the "/g" option is not used, "m//" in list context returns a
list consisting of the subexpressions matched by the
parentheses in the pattern, i.e., ($1, $2, $3...).
Try <(("[^"]*"|'[^']*'|[^'">])*)>(\w+)<\/\1>. Should work, when I get home I'll test it. The idea is that the first capture group finds the contents within a <> and its nested capture group prevents a situation like <blah=">"> matching as <blah=">. The third capture group (\w+) matches the inner word. This may have to be changed depending on the format of the possibilities you can have within the <tag>content</tag>. Lastly the \1 looks back at the content of the first capture group so that this way you will find the proper closing tag.
Edit: I've tested this with perl and it works.