I have something like:
$string = '/mfsi_rpt/files/mfsi/reports/bval/bval_parlcont_pck_m_20130430.pdf';
I would like to extract the parlcont from the string (the word between the 2nd and 3rd underscore).
What is the best way to achieve this using Perl?
You can match this with a regular expression, by combining greedy and non-greedy matches, and using capturing parenthesis to extract the part you're interested in:
if( $string =~ m:.+/.*?_(.+?)_:) {
print "$1\n";
}
The ".+/" is a greedy match, which will gobble up everything up to the last / to get past the directory components.
Then the ".*?_" is non-greedy, so it will take everything up to the first _
Then "(.+?)_" is another non-greedy to match and capture everything up to the next _
It would be nice if you first take out the filename from the file path using File::Basename then you can use split to take out the desired name.
use strict;
use File::Basename;
my $string = "/mfsi_rpt/files/mfsi/reports/bval/bval_parlcont_pck_m_20130430.pdf";
my $data = ( split( /_/, basename($string) ))[1];
Output:
parlcont
Related
What is wrong specifically with this code? How can I correct it?
$x = "without any vowels after the first letter\n";
foreach $i (#x[1..]) {
if ($i =~ /[AEIOUaeiou]/) {
$x =~ tr/A E I O U a e i o u//d;
}
}
print "$x\n";
I tried [1..] to exclude the first letter. If it does not work, how else can I remove the first letter?
EDIT I edited code to make it syntactically (mostly) correct to convey their obvious original idea, except for the attempt to index into a string which isn't correct in Perl. (Clarifying that is a part of what I consider useful in this question.)
First, most of that is not Perl, or any programming language for that matter. I'd suggest to work through a Perl tutorial of your choice first, before trying to get solutions for specific problems. However, here's an answer since the problem itself is of enough interest in general.
Next, in Perl you can't directly index into a string, so you can't skip the first character(s) like that.
But you can separate that first character in the string and process the rest (removing vowels), of course. One way with regex†
use warnings;
use strict;
use feature 'say';
my $str = shift // 'out with ALL vowels after first';
$str =~ s/.\K(.*)/ $1 =~ tr{[aeiouAEIOU]}{}dr /e;
say $str; #--> ot wth LL vwls ftr frst
This relies on the /e modifier, which makes it so that the replacement side is evaluated as code, and so it runs an independent transliteration (tr) there, processing the captured substring.
Then we need the /r modifier in that embedded tr/regex, to return the new string instead of changing the old one in place -- what wouldn't be possible anyway as one can't change $1.
One can also use a regex insteda of tr, less efficient but with its many conveniences
$str =~ s/.\K(.*)/ $1 =~ s{[aeiou]}{}igr /e;
Now we can use far more sophisticated tools in that regex than in tr; in this case it's only the i flag, for case-insensitive.
If it were more than the one first character to keep change . to .{N}.
† Regex is not compulsory, of course. A more elementary take: split the string into its first character and the rest, then use tr on the rest
use warnings;
use strict;
use feature 'say';
my $str = shift // q(out with ALL vowels after first);
my ($result, $rest) = split //, $str, 2; # first char, rest of string
$result .= $rest =~ tr/aeiouAEIOU//dr; # prune $rest of vowels, append to $result
say $result;
Then put this in a little mini subroutine. To change the original string in place, instead of getting a new ($result) string, use it ($str) everywhere instead of $result.
I am not sure about how it compares efficiency wise but it may well fare well.
For the curiosity's sake, here it is in a single statement
$str = join '', map { length > 1 ? tr/aeiouAEIOU//dr : $_ } split //, $str, 2;
This specifically uses the fact that only the first (one) character need be skipped; that is easily made dynamical, as long as the criterion does involve the length of substrings.
More importantly, this assumes that the rest of the string is longer than 1 character. To drop that assumption change the criterion
use feature 'state';
$str = join '', map {
state $chr_cnt = 0;
++$chr_cnt > 1 ? tr/aeiouAEIOU//dr : $_
}
split //, $str, 2;
This also relies on leaving aside just one character. It uses a feature to keep a lexical value across executions, state.
A more generic solution, which uses the property of substr to be possible to write to
substr($str, 1) =~ tr/aeiouAEIOU//d;
Here it's much cleaner and simpler to relax the limitation to the first character: just change that 1 in order to skip more characters. The tricky -- unexpected -- part here may be that normally builtins can't be written to like that, they aren't lvalue subroutines
The algorithm for solution of the problem is in your question
add letter to a string if it isn't vowel
add letter to the string if it is first vowel in the input string
use strict;
use warnings;
my $x = "without any vowels after the first letter\n";
my($o,$count) = ('',0);
print 'IN: ' . $x;
for ( split('',$x) ) {
$o .= $_ unless $count != 0 and /[aeiou]/i;
$count++ if /[aeiou]/i;
}
print 'OUT: ' . $o;
Output
IN: without any vowels after the first letter
OUT: witht ny vwls ftr th frst lttr
Addendum: OP's clarification of the problem
look at each word in the sentence
if a word starts from vowel then delete all vowels but first one
if a word starts from none vowel then delete all vowels
use strict;
use warnings;
use feature 'say';
my $x = 'I like apples more than oranges';
my #o;
say 'IN: ' . $x;
for ( split(' ', $x) ) {
if ( /^[aeiou]/i ) {
s/.\K(.*)/$1 =~ tr|aeiouAEIOU||dr/e;
} else {
tr|aeiouAEIOU||d;
}
#o = (#o,$_);
}
say 'OUT: ' . join(' ', #o);
Output
IN: I like apples more than oranges
OUT: I lk appls mr thn orngs
Or in perlish style
use strict;
use warnings;
use feature 'say';
my $x = "I like apples more than oranges";
say 'IN: ' . $x;
say 'OUT: ' . join(' ', map { s/.\K(.*)/$1 =~ tr|aeiouAEIOU||dr/e && $_ } split('[ ]+', $x));
Output
IN: I like apples more than oranges
OUT: I lk appls mr thn orngs
my $book = Spreadsheet::Read->new();
my $book = ReadData
('D:\Profiles\jmahroof\Desktop\Scheduled_Build_Overview.xls');
my $cell = "CD7";
my $n = "1";
my $send = $book->[$n]{$cell};
The above code gets data from a spreadsheet, then prints the content of a cell that I know has text in. It has text of exactly the following format: text(text)
I need to replace the open bracket with a empty space and I need to remove the close bracket. I have tried the below code to substitute the open bracket for an empty space however it does not seem to work.
$send =~ s/(/ /g;
print $send;
The bracket is seen as part of the code, just escape it.
$send =~ s/\(/ /;
print $send;
Since you only replace one char with another, you don't want a substitution, but a transliteration. That's the tr/// function in Perl. Since the pattern is just a list of chars, and not an actual regex, you don't need to escape the open parenthesis (. There is also no /g flag. It just substitutes all occurrences.
$send =~ tr/(/ /;
The main difference to a regular expression substitution is that the transliterations get compiled at compile time, not at run time. That makes the tr/// faster than a s///, especially in a loop.
See the full documentation in perlop.
I'm trying to edit the numbers in a string and put it back in the same place as they have been before.
Example:
$string = "struct:{thin:[[75518103,75518217],[75518338,75518363],[75532810,75533910],],thick:[[75518363,75518424],[75521257,75521463],],}";
I need to edit the numbers, but want to keep the rest of the string at it is. Additionally the number of brackets can vary.
Until now I split the string at "," with
#array = split (',',$string);
and extracted the numbers for editing with
foreach (#array) {
$_ =~ s/\D//g;
$_ = $number - $_;
}
now I want to put the numbers back in their original place in the string, but I don't know how.
Somehow I hope there is a better way to edit the numbers in the string without splitting it and extracting the numbers. Hope you can help me
You could use a regular expression substitution with the /e flag, search for long numbers and run Perl code in the substitution part.
use strict;
use warnings;
use feature 'say';
my $number = 100_000_000;
my $string = "struct:{thin:[[75518103,75518217],[75518338,75518363],[75532810,75533910],],thick:[[75518363,75518424],[75521257,75521463],],}";
$string =~ s/(\d+)/{$number - $1}/eg;
say $string;
__END__
struct:{thin:[[24481897,24481783],[24481662,24481637],[24467190,24466090],],thick:[[24481637,24481576],[24478743,24478537],],}
If there are no other numbers in the string, that would work. In case there is more logic involved, you can also move it into a subroutine and just call that in the substitution.
sub replace {
return $_ % 2 ? $_ * 2 : $_ / 4;
}
$string =~ s/(\d+)/{replace($1)}/eg;
You might also need to revise the search pattern to be a bit more precise.
I just found the evaluation modifier for regex! I now did it with
$string =~ s/([0-9]+)/$number-$1/eg;
and it worked!
I have a string that looks like this
Acanthocolla_cruciata,#8B5F65Acanthocyrta_haeckeli,#8B5F65Acanthometra_fusca,#8B5F65Acanthopeltis_japonica,#FFB5C5
I am trying to added in new lines so get in list format. Like this
Acanthocolla_cruciata,#8B5F65
Acanthocyrta_haeckeli,#8B5F65
Acanthometra_fusca,#8B5F65
Acanthopeltis_japonica,#FFB5C5
I have a perl script
use strict;
use warnings;
open my $new_tree_fh, '>', 'test_match.txt'
or die qq{Failed to open "update_color.txt" for output: $!\n};
open my $file, '<', $ARGV[0]
or die qq{Failed to open "$ARGV[0]" for input: $!\n};
while ( my $string = <$file> ) {
my $splitmessage = join ("\n", ($string =~ m/(.+)+\,+\#+\w{6}/gs));
print $new_tree_fh $splitmessage, "\n";
}
close $file;
close $new_tree_fh;
The pattern match works but it wont print the new line as I want to make the list. Can anyone please suggest anything.
I'd do:
my $str = 'Acanthocolla_cruciata,#8B5F65Acanthocyrta_haeckeli,#8B5F65Acanthometra_fusca,#8B5F65Acanthopeltis_japonica,#FFB5C5';
$str =~ s/(?<=,#\w{6})/\n/g;
say $str;
Output:
Acanthocolla_cruciata,#8B5F65
Acanthocyrta_haeckeli,#8B5F65
Acanthometra_fusca,#8B5F65
Acanthopeltis_japonica,#FFB5C5
OK, I think your problem here is that your regular expression doesn't match properly.
(.+)+
for example - probably doesn't do what you think it does. It's a greedy capture of 1 or more of "anything" which will grab your whole string.
Check it out on regex101.
Try:
#!/usr/bin/perl
use strict;
use warnings;
while ( my $string = <DATA> ) {
my $splitmessage = join( "\n", ( $string =~ m/(\w+,\#+\w{6})/g ) );
print $splitmessage, "\n";
}
__DATA__
Acanthocolla_cruciata,#8B5F65Acanthocyrta_haeckeli,#8B5F65Acanthometra_fusca,#8B5F65Acanthopeltis_japonica,#FFB5C5
Which will print:
Acanthocolla_cruciata,#8B5F65
Acanthocyrta_haeckeli,#8B5F65
Acanthometra_fusca,#8B5F65
Acanthopeltis_japonica,#FFB5C5
Rather than a quickfix solution, let's find the problem in your existing code and hence learn from it. Your problem is in the regular expression, so we'll dissect and fix it.
($string =~ m/(.+)+\,+\#+\w{6}/gs)
First, the two significant mistakes that lead to the bug:
At the beginning, you're doing a .+, followed by matching with , and # and so on. The problem is, .+ is greedy, which means it'll match upto the last , in the input, and not the first one. So when you run this, almost the entire line (except for the last plant's color) gets matched up by this single .+.
There are a few different ways you can fix this, but the easiest is to restrict what you're matching. Instead of saying .+ "match anything", make it [\w\s]+ at the beginning - which means match either "word characters" (which includes alphabets and digits) or space characters (since there is a space in the middle of the plant name).
($string =~ m/([\w\s]+)+\,+\#+\w{6}/gs)
That changes the output, but still not to the fully correct version because:
m/some regex/g returns a list of its matches as a list here, and what we want is for it to return the whole match including both plant name and color. But, when there are paranthesis inside the match anywhere, m/ returns only the part matched by the paranthesis (which is the plant name here), not the whole match. So, remove the paranthesis, and it becomes:
($string =~ m/[\w\s]++\,+\#+\w{6}/gs)
This works, but is quite clumsy and bug-prone, so here's some improvement suggestions:
Since your input has no newline characters, the /s at the end is unnecessary.
($string =~ m/[\w\s]++\,+\#+\w{6}/g)
, and # are not a special character in perl regular expressions, so they don't need a \ before them.
($string =~ m/[\w\s]++,+#+\w{6}/g)
+ is for when you know only that the character will be present, but don't know how many times it'll be there. Here, since we're only trying to match one , and one # characters, the + after them is unnecessary.
($string =~ m/[\w\s]++,#\w{6}/g)
The ++ after [\w\s] means something quite different from + (basically an even greedier match than usual), so let's make it a single +
($string =~ m/[\w\s]+,#\w{6}/g)
Optionally, you can change the last \w to match only the hexadecimal characters which will appear in the colour code:
($string =~ m/[\w\s]+,#[0-9A-F]{6}/g)
That's a pretty solid, working regular expression that does what you want.
i want to retrive the last two columns of a string
ex
$path = C:\Documents and Settings\ac62599\AC62599_SBI_Release_2012.12.1_int\vob\SBI_src
$path = C:\views\ac62599\AC62599_view\vob\aims
output should be
\vob\SBI_src
\vob\aims
output should come like this . Thanks in advance
Use split to split the paths into directories. You can use a slice to get the last two, then use join to concatenate them back:
for my $path ('C:\Documents and Settings\ac62599\AC62599_SBI_Release_2012.12.1_int\vob\SBI_src',
'C:\views\ac62599\AC62599_view\vob\aims') {
print '\\', join('\\', (split/\\/, $path)[-2, -1]), "\n";
}
A regex seems to be the simplest solution
my ($dir) = $path =~ /((?:\\[^\\]+){2})$/;
Which is to say, look for backslash, followed by one or more non-backslash characters, and look for this sequence twice at the end of the string and capture it.
Note the use of parentheses around the variable is required to give the regex list context.
Output for the sample paths:
\vob\SBI_src
\vob\aims
$string=~m/.*(\\[^\\]*\\[^\\]*)/g;print $1