I am trying to write a common regular expression for the below 3 cases:
Supernatural_S07E23_720p_HDTV_X264-DIMENSION.mkv
the.listener.313.480p.hdtv.x264-2hd.mkv
How.I.met.your.mother.s02e07.hdtv.x264-xor.avi
Now my regular exoression should remove the series name from the original string i,e the output of above string will be:
S07E23_720p_HDTV_X264-DIMENSION.mkv
313.480p.hdtv.x264-2hd.mkv
s02e07.hdtv.x264-xor.avi
Now for the basic case of supernatural string I wrote the below regex and it worked fine but as soon as the series name got multiple words it fails.
$string =~ s/^(.*?)[\.\_\- ]//i; #delimiter can be (. - _ )
So, I have no idea how to proceed for the aboves cases I was thinking along the lines of \w+{1,6} but it also failed to do the required.
PS: Explanation of what the regular expression is doing will be appreciated.
you can detect if the .'s next token contains digit, if not, consider it as part of the name.
HOWEVER, I personally think there is no perfect solution for this. it'd still meet problem for something like:
24.313.480p.hdtv.x264-2hd.mkv // 24
Warehouse.13.s02e07.hdtv.x264-xor.avi // warehouse 13
As StanleyZ said, you'll always get into trouble with names containing numbers.
But, if you take these special cases appart, you can try :
#perl
$\=$/;
map {
if (/^([\w\.]+)[\.\_]([SE\d]+[\.\_].*)$/i) {
print "Match : Name='$1' Suffix='$2'";
} else {
print "Did not match $_";
}
}
qw!
Supernatural_S07E23_720p_HDTV_X264-DIMENSION.mkv
the.listener.313.480p.hdtv.x264-2hd.mkv
How.I.met.your.mother.s02e07.hdtv.x264-xor.avi
!;
which outputs :
Match : Name='Supernatural' Suffix='S07E23_720p_HDTV_X264-DIMENSION.mkv'
Match : Name='the.listener' Suffix='313.480p.hdtv.x264-2hd.mkv'
Match : Name='How.I.met.your.mother' Suffix='s02e07.hdtv.x264-xor.avi'
note : aren't you doing something illegal ? ;)
Related
I am downloading a webpage and converting into a string using LWP::Simple. When I copy the results into an editor I find multiple instances of the pattern I'm looking for "data-src-hq".
While I'm trying to do something more complex using regex I am starting in baby steps so I can properly learn how to use regex, I started off with just to match "data-src-hq" with the following code:
if($html =~ /data-src-hq/ism)
{
print "match\n";
}
else
{
print "nope\n";
}
My code returns "nope". However, if I modify the pattern search to just "data" or "data-src" I do get a match. The same happens no matter how I use and combine the string and multiline modifier.
My understanding is that a hyphen is not a special character unless it's within brackets, am I missing something simple?
How to fix this?
You are likely getting two outputs, one of match and one of nope. Your code is missing the keyword else:
See your code's current execution here
if($html =~ /data-src-hq/ism)
{
print "match\n";
}
{
print "nope\n";
}
Should be:
See this code's execution here
if($html =~ /data-src-hq/ism)
{
print "match\n";
}
else {
print "nope\n";
}
Otherwise, your code is fine and works to identify whether data-src-hq exists in $html.
So why does your existing code output nope?
That's because {} is a basic block (see Basic BLOCKs in Perl's documentation). An excerpt from the documentation:
A BLOCK by itself (labeled or not) is semantically equivalent to a
loop that executes once. Thus you can use any of the loop control
statements in it to leave or restart the block. (Note that this is NOT
true in eval{}, sub{}, or contrary to popular belief do{} blocks,
which do NOT count as loops.) The continue block is optional.
In have following code:
set[str] noNnoE = { v | str v <- eu, (/\b[^eEnN]*\b/ := v) };
The goal is to filter out of a set of strings (called 'eu'), those strings that have no 'e' or 'n' in them (both upper- and lowercase). The regular expression I've provided:
/\b[^eEnN]?\b/
seems to work like it should, when I try it out in an online regex-tester.
When trying it out in the Rascel terminal it doesn't seem to work:
rascal>/\b[^eEnN]*\b/ := "Slander";
bool: true
I expected no match. What am I missing here? I'm using the latest (stable) Rascal release in Eclipse Oxygen1a.
Actually, the online regex-tester is giving the same match that we are giving. You can look at the match as follows:
if (/<w1:\b[^eEnN]?\b>/ := "Slander")
println("The match is: |<w1>|");
This is assigning the matched string to w1 and then printing it between the vertical bars, assuming the match succeeds (if it doesn't, it returns false, so the body of the if will not execute). If you do this, you will get back a match to the empty string:
The match is: ||
The online regex tester says the same thing:
Match 1
Full match 0-0 ''
If you want to prevent this, you can force at least one occurrence of the characters you are looking for by using a +, versus a ?:
rascal>/\b[^eEnN]+\b/ := "Slander";
bool: false
Note that you can also make the regex match case insensitive by following it with an i, like so:
/\b[^en]+\b/i
This may make it easier to write if you need to add more characters into the character class.
This solution (/\b[^en]+\b/i) doesn't work for strings consisting of two words, such as the Czech Republic.
Try /\b[^en]+\b$/i. That seems to work for me.
I am new to Pig. In the script that I am writing I want to perform an operation similar to this:
foreach X GENERATE REPLACE(word,'.*abc.*','abc') OR REPLACE(word,'.*def.*','def').
If the first pattern matches then abc is replaced else if second pattern is matched then def is replaced. But I suppose the syntax is incorrect. Can someone help me with the syntax?
There are a few ways to do this, but since if the regex doesn't match the string, you'll just get your string back, this is pretty compact:
Y = FOREACH X GENERATE REPLACE(REPLACE(word, '.*abc.*', 'abc'), '.*def.*', 'def');
I am using perl and regular expression to find an ORF (open reading frame) with a minimal size of 45 bases using.
Basically it means:
Find a substring a string that is composed ONLY of the letters ATGC (no spaces or new lines) that:
Starts with "ATG"
ends with "TAG" or "TAA" or "TGA",
is at least 39 chars long
is dividable by 3
My first code was:
$CDSString = "ATGCACACACACACACACACACACACACACACACACACACACACACACACACACACATGA";
if($CDSString =~ m/(ATG.{45,}(TAG|TAA|TGA))/)
{
my $CDSCurrent = $1;
if ((length($CDSCurrent) % 3) == 0)
{
# do something
}
}
which works fine, but I thought there might be a better way.
So I tried:
$CDSString = "ATGCACACACACACACACACACACACACACACACACACACACACACACACACACACATGA";
if ($CDSString =~ m/ATG(...){13,}(TAG|TAA|TGA)/ )
{
# do something
}
but for some reason it doesn't match the string above it, and I can't figure out why.
Can anyone figure it out? Thank you in advance.
Your regex is not making sure that everything between the start and stop codons is in fact composed of the letters ATGC only. You should be using:
if ($CDSString =~ m/ATG(?:[ATGC]{3}){13,}(?:TAG|TAA|TGA)/i) {...}
(But your original regex works, too, it just won't reject invalid matches. So there may be another problem somewhere else.)
There is a problem with the code thus far. What you should be looking for is the FIRST instance of a stop codon. If your CDS is no good, it might contain internal stops. Internal stop codons make an invalid ORF, so you need something more finessed:
if($CDSString =~ m/ATG(?:[ATGC]{3}(?<!TAG|TAA|TGA)){13,}(?:TAG|TAA|TGA)/i) {...}
This will return a sequence without internal stops that has at least 13 codons between the start and the first stop.
This portion of the code: (?:[ATGC]{3}(?<!TAG|TAA|TGA)) says "match three nucleotides that are not TAG, TAA, or TGA". The (?
Here's how it looks in action:
perl -e '$CDSString = "ATGCACACACACACACACACACACACACACACACACACACACACACACACACACACATAGTAGTAGTGA";if ($CDSString =~ m/(ATG(?:[ATGC]{3}(?<\!TAG|TAA|TGA)){13,}(TAG|TAA|TGA))/ ){print "$1\n"}'
ATGCACACACACACACACACACACACACACACACACACACACACACACACACACACATAG
Note, the last 3 stop codons (TAGTAGTGA) are not returned as part of the sequence.
I want to use a regular expression that would do the following thing ( i extracted the part where i'm in trouble in order to simplify ):
any character for 1 to 5 first characters, then an "underscore", then some digits, then an "underscore", then some digits or dot.
With a restriction on "underscore" it should give something like that:
^([^_]{1,5})_([\\d]{2,3})_([\\d\\.]*)$
But i want to allow the "_" in the 1-5 first characters in case it still match the end of the regular expression, for example if i had somethink like:
to_to_123_12.56
I think this is linked to an eager problem in the regex engine, nevertheless, i tried to do some lazy stuff like explained here but without sucess.
Any idea ?
I used the following regex and it appeared to work fine for your task. I've simply replaced your initial [^_] with ..
^.{1,5}_\d{2,3}_[\d\.]*$
It's probably best to replace your final * with + too, unless you allow nothing after the final '_'. And note your final part allows multiple '.' (I don't know if that's what you want or not).
For the record, here's a quick Python script I used to verify the regex:
import re
strs = [ "a_12_1",
"abc_12_134",
"abcd_123_1.",
"abcde_12_1",
"a_123_123.456.7890.",
"a_12_1",
"ab_de_12_1",
]
myre = r"^.{1,5}_\d{2,3}_[\d\.]+$"
for str in strs:
m = re.match(myre, str)
if m:
print "Yes:",
if m.group(0) == str:
print "ALL",
else:
print "No:",
print str
Output is:
Yes: ALL a_12_1
Yes: ALL abc_12_134
Yes: ALL abcd_134_1.
Yes: ALL abcde_12_1
Yes: ALL a_123_123.456.7890.
Yes: ALL a_12_1
Yes: ALL ab_de_12_1
^(.{1,5})_(\d{2,3})_([\d.]*)$
works for your example. The result doesn't change whether you use a lazy quantifier or not.
While answering the comment ( writing the lazy expression ), i saw that i did a mistake... if i simply use the folowing classical regex, it works:
^(.{1,5})_([\\d]{2,3})_([\\d\\.]*)$
Thank you.