I have a fixed message delimited by "|"... tag=value is the pair between the delimiter;
(8=FIX.4.2|9=0360|35=8|49=BLPFT|56=ESP|34=8415|52=20110201-15:59:59|50=MBA|143=LN|115=MSET|57=2457172|30=CHIX|60=20110201-15:59:59.121|150=1|31=56.3100|151=71785|32=137|6=56.4058|37=9D9ZIhgu4BGU9sBtfHcYeQA|38=97370|39=1|40=1|11=20110201-05529|12=0.0012|13=2|14=25585|15=EUR|76=CHIXCCP|17=272674|47=A|167=CS|18=1|48=FR0000131104|20=0|21=1|22=4|113=N|54=1|55=BNP|207=FP|29=1|59=0|10=205|)
How to extract a data between "11=" and a first occurrence of "|" after a match?
For example i want a data
20110201-05529
which is between "|11=" and "|"
Can you please tell me the regular expression?
The best approach will depend on how much you know about the data you are trying to match. If you know it will be comprised of numbers and dashes only:
m/11=([0-9\-]+)/
Conversely, if the data could contain any kind of characters, use:
m/11=([^|]+)/
Which matches anything that isn't a pipe character. This is probably the most reliable expression.
In both cases, the data you want is captured into the $1 special variable.
If you don't always want to match the value for the key 11, you can use variables in the pattern, so:
my $key = 42; # or any number
if ($text =~ m/$key=([^|]+)/) {
print "I found $1"; # prints "I found 20110201-05529"
}
As always, there is more than 1 way to solve the problem. Therefore, there is no such thing as "the regular expression".
But you will definitely want to perldoc split.
Something like this will match everything else than = then everything else than |
[^=]+=([^|])+
Related
Example data:
029Extract this specific string. Do not capture anything else.
In the example above, I would like to capture the first n characters immediately after the 3 digit entry which defines the value of n. I.E. the 29 characters "Extract this specific string."
I can do this within a loop, but it is slow. I would like (if it is possible) to achieve this with a single regex statement instead, using some kind of backreference. Something like:
(\d{3})(.{\1})
With perl, you can do:
my $str = '029Extract this specific string. Do not capture anything else.';
$str =~ s/^(\d+)(.*)$/substr($2,0,$1)/e;
say $str;
output:
Extract this specific string.
You can not do it with single regex, while you can use knowledge where regex stop processing to use substr. For example in JavaScript you can do something like this http://jsfiddle.net/75Tm5/
var input = "blahblah 011I want this, and 029Extract this specific string. Do not capture anything else.";
var regex = /(\d{3})/g;
var matches;
while ((matches = regex.exec(input)) != null) {
alert(input.substr(regex.lastIndex, matches[0]));
}
This will returns both lines:
I want this
Extract this specific string.
Depending on what you really want, you can modify Regex to match only numbers starting from line beginning, match only first match etc
Are you sure you need a regex?
From https://stackoverflow.com/tags/regex/info:
Fools Rush in Where Angels Fear to Tread
The tremendous power and expressivity of modern regular expressions
can seduce the gullible — or the foolhardy — into trying to use
regular expressions on every string-related task they come across.
This is a bad idea in general, ...
Here's a Python three-liner:
foo = "029Extract this specific string. Do not capture anything else."
substr_len = int(foo[:3])
print foo[3:substr_len+3]
And here's a PHP three-liner:
$foo = "029Extract this specific string. Do not capture anything else.";
$substr_len = (int) substr($foo,0,3);
echo substr($foo,3,substr_len+3);
I am trying to extract email address from a txt file. I've thought about surrounding words that contain the '#' character. Does anybody know a expression to do that?
Whenever you need some reasonably common matching problem resolve in Perl, you should always first check the Regexp::Common family on CPAN. In this case: Regexp::Common::Email::Address. From POD Synopsys:
use Regexp::Common qw[Email::Address];
use Email::Address;
while (<>) {
my (#found) = /($RE{Email}{Address})/g;
my (#addrs) = map $_->address, Email::Address->parse("#found");
print "X-Addresses: ", join(", ", #addrs), "\n";
}
Here's a very quick and dirty regex which will match non-whitespace characters on either side of an #:
/\S+#\S+/
This will match john.smith#example.com in
some rubbish text john.smith#example.com more rubbish text
Hope this helps.
I have following text pattern
(2222) First Last (ab-cd/ABC1), <first.last#site.domain.com> 1224: efadsfadsfdsf
(3333) First Last (abcd/ABC12), <first.last#site.domain.com> 1234, 4657: efadsfadsfdsf
I want the number 1224 or 1234, 4657 from the above text after the text >.
I have this
\((\d+)\)\s\w*\s\w*\s\(\w*\/\w+\d*\),\s<\w*\.\w*\#\w*\.domain.com>\s\d+:
which will take the text before : But i want the one after email till :
Is there any easy regular expression to do this? or should I use split and do this
Thanks
Edit: The whole text is returned by a command line tool.
(3333) First Last (abcd/ABC12), <first.last#site.domain.com> 1234, 4657: efadsfadsfdsf
(3333) - Unique ID
First Last - First and last names
<first.last#site.domain.com> - Email address in format FirstName.LastName#sub.domain.com
1234, 4567 - database primary Keys
: xxxx - Headline
What I have to do is process the above and get hte database ID (in ex: 1234, 4567 2 separate ID's) and query the tables
The above is the output (like this I will get many entries) from the tool which I am calling via my Perl script.
My idea was to use a regular expression to get the database id's. Guess I could use regular expression for this
you can fudge the stuff you don't care about to make the expression easier, say just 'glob' the parts between the parentheticals (and the email delimiters) using non-greedy quantifiers:
/(\d+)\).*?\(.*?\),\s*<.*?>\s*(\d+(?:,\s*\d+)*):/ (not tested!)
there's only two captured groups, the (1234), and the (1234, 4657), the second one which I can only assume from your pattern to mean: "a digit string, followed by zero or more comma separated digit strings".
Well, a simple fix is to just allow all the possible characters in a character class. Which is to say change \d to [\d, ] to allow digits, commas and space.
Your regex as it is, though, does not match the first sample line, because it has a dash - in it (ab-cd/ABC1 does not match \w*\/\w+\d*\). Also, it is not a good idea to rely too heavily on the * quantifier, because it does match the empty string (it matches zero or more times), and should only be used for things which are truly optional. Use + otherwise, which matches (1 or more times).
You have a rather strict regex, and with slight variations in your data like this, it will fail. Only you know what your data looks like, and if you actually do need a strict regex. However, if your data is somewhat consistent, you can use a loose regex simply based on the email part:
sub extract_nums {
my $string = shift;
if ($string =~ /<[^>]*> *([\d, ]+):/) {
return $1 =~ /\d+/g; # return the extracted digits in a list
# return $1; # just return the string as-is
} else { return undef }
}
This assumes, of course, that you cannot have <> tags in front of the email part of the line. It will capture any digits, commas and spaces found between a <> tag and a colon, and then return a list of any digits found in the match. You can also just return the string, as shown in the commented line.
There would appear to be something missing from your examples. Is this what they're supposed to look like, with email?
(1234) First Last (ab-cd/ABC1), <foo.bar#domain.com> 1224: efadsfadsfdsf
(1234) First Last (abcd/ABC12), <foo.bar#domain.com> 1234, 4657: efadsfadsfdsf
If so, this should work:
\((\d+)\)\s\w*\s\w*\s\(\w*\/\w+\d*\),\s<\w*\.\w*\#\w*\.domain\.com>\s\d+(?:,\s(\d+))?:
$string =~ /.*>\s*(.+):.+/;
$numbers = $1;
That's it.
Tested.
With number catching:
$string =~ /.*>\s*(?([0-9]|,)+):.+/;
$numbers = $1;
Not tested but you get the idea.
I have a text input field for titles of various things and to help minimize false negatives on search results(internal search is not the best), I need to have a REGEX pattern which looks at the first four characters of the input string and removes the word(and space after the word) _the _ if it is there at the beginning only.
For example if we are talking about the names of bands, and someone enters The Rolling Stones , what i need is for the entry to say only Rolling Stones
Can a regex be used to automatically strip these 4characters?
Applying the regex
^(?:\s*the\s*)?(.*)$
will match any string, and capture it in backreference no. 1, unless it starts with the (optionally surrounded by whitespace), in which case backref no. 1 will contain whatever follows.
You need to set the case-insensitive option in your regex engine for this to work.
You can use the ^ identifier to match a pattern at the beginning of a line, however for what you are using this for, it can be considered overkill.
A lot of languages support string manipulations, which is a more suitable choice. I can provide an example to demonstrate in Python,
>>> def func(n):
n = n[4:len(n)] if n[0:4] == "The " else n
return n
>>> func("The Rolling Stones")
'Rolling Stones'
>>> func("They Might Be Giants")
'They Might Be Giants'
As you don't clarify with language, here is a solution in Perl :
my $str = "The Rolling Stones";
$str =~ s/^the //i;
say $str; # Rolling Stones
As stated in the title, is there a way, using regular expressions, to match a text pattern for text that appears outside of quotes. Ideally, given the following examples, I would want to be able to match the comma that is outside of the quotes, but not the one in the quotes.
This is some text, followed by "text, in quotes!"
or
This is some text, followed by "text, in quotes" with more "text, in quotes!"
Additionally, it would be nice if the expression would respect nested quotes as in the following example. However, if this is technically not feasible with regular expressions then it wold simply be nice to know if that is the case.
The programmer looked up from his desk, "This can't be good," he exclaimed, "the system is saying 'File not found!'"
I have found some expressions for matching something that would be in the quotes, but nothing quite for something outside of the quotes.
Easiest is matching both commas and quoted strings, and then filtering out the quoted strings.
/"[^"]*"|,/g
If you really can't have the quotes matching, you could do something like this:
/,(?=[^"]*(?:"[^"]*"[^"]*)*\Z)/g
This could become slow, because for each comma, it has to look at the remaining characters and count the number of quotes. \Z matches the end of the string. Similar to $, but will never match line ends.
If you don't mind an extra capture group, it could be done like this instead:
/\G((?:[^"]*"[^"]*")*?[^"]*?)(,)/g
This will only scan the string once. It counts the quotes from the beginning of the string instead. \G will match the position where last match ended.
The last pattern could need an example.
Input String: 'This is, some text, followed by "text, in quotes!" and more ,-as'
Matches:
1. ['This is', ',']
2. [' some text', ',']
3. [' and followed by "text, in quotes!" and more ', ',']
It matches the string leading up to the comma, as well as the comma.
This can be done with modern regexes due to the massive number of hacks to regex engines that exist, but let me be the one to post the "Don't Do This With Regular Expressions" answer.
This is not a job for regular expressions. This is a job for a full-blown parser. As an example of something you can't do with (classical) regular expressions, consider this:
()(())(()())
No (classical) regex can determine if those parenthesis are matched properly, but doing so without a regex is trivial:
/* C code */
char string[] = "()(())(()())";
int parens = 0;
for(char *tmp = string; tmp; tmp++)
{
if(*tmp == '(') parens++;
if(*tmp == ')') parens--;
}
if(parens > 0)
{
printf("%s too many open parenthesis.\n", parens);
}
else if(parens < 0)
{
printf("%s too many closing parenthesis.\n", -parens);
}
else
{
printf("Parenthesis match!\n");
}
# Perl code
my $string = "()(())(()())";
my $parens = 0;
for(split(//, $string)) {
$parens++ if $_ eq "(";
$parens-- if $_ eq ")";
}
die "Too many open parenthesis.\n" if $parens > 0;
die "Too many closing parenthesis.\n" if $parens < 0;
print "Parenthesis match!";
See how simple it was to write some non-regex code to do the job for you?
EDIT: Okay, back from seeing Adventureland. :) Try this (written in Perl, commented to help you understand what I'm doing if you don't know Perl):
# split $string into a list, split on the double quote character
my #temp = split(/"/, $string);
# iterate through a list of the number of elements in our list
for(0 .. $#temp) {
# skip odd-numbered elements - only process $list[0], $list[2], etc.
# the reason is that, if we split on "s, every other element is a string
next if $_ & 1;
if($temp[$_] =~ /regex/) {
# do stuff
}
}
Another way to do it:
my $bool = 0;
my $str;
my $match;
# loop through the characters of a string
for(split(//, $string)) {
if($_ eq '"') {
$bool = !$bool;
if($bool) {
# regex time!
$match += $str =~ /regex/;
$str = "";
}
}
if(!$bool) {
# add the current character to our test string
$str .= $_;
}
}
# get trailing string match
$match += $str =~ /regex/;
(I give two because, in another language, one solution may be easier to implement than the other, not just because There's More Than One Way To Do It™.)
Of course, as your problems grow in complexity, there will arise certain benefits of constructing a full-blown parser, but that's a different horse. For now, this will suffice.
As mentioned before, regexp cannot match any nested pattern, since it is not a Context-free language.
So if you have any nested quotes, you are not going to solve this with a regex.
(Except with the "balancing group" feature of a .Net regex engine - as mentioned by Daniel L in the comments - , but I am not making any assumption of the regex flavor here)
Except if you add further specification, like a quote within a quote must be escaped.
In that case, the following:
text before string "string with \escape quote \" still
within quote" text outside quote "within quote \" still inside" outside "
inside" final outside text
would be matched successfully with:
(?ms)((?:\\(?=")|[^"])+)(?:"((?:[^"]|(?<=\\)")+)(?<!\\)")?
group1: text preceding a quoted text
group2: text within double quotes, even if \" are present in it.
Here is an expression that gets the match, but it isn't perfect, as the first match it gets is the whole string, removing the final ".
[^"].*(,).*[^"]
I have been using my Free RegEx tester to see what works.
Test Results
Group Match Collection # 1
Match # 1
Value: This is some text, followed by "text, in quotes!
Captures: 1
Match # 2
Value: ,
Captures: 1
You should better build yourself a simple parser (pseudo-code):
quoted := False
FOR char IN string DO
IF char = '"'
quoted := !quoted
ELSE
IF char = "," AND !quoted
// not quoted comma found
ENDIF
ENDIF
ENDFOR
This really depends on if you allow nested quotes or not.
In theory, with nested quotes you cannot do this (regular languages can't count)
In practice, you might manage if you can constrain the depth. It will get increasingly ugly as you add complexity. This is often how people get into grief with regular expressions (trying to match something that isn't actually regular in general).
Note that some "regex" libraries/languages have added non-regular features.
If this sort of thing gets complicated enough, you'll really have to write/generate a parser for it.
You need more in your description. Do you want any set of possible quoted strings and non-quoted strings like this ...
Lorem ipsum "dolor sit" amet, "consectetur adipiscing" elit.
... or simply the pattern you asked for? This is pretty close I think ...
(?<outside>.*?)(?<inside>(?=\"))
It does capture the "'s however.
Maybe you could do it in two steps?
First you replace the quoted text:
("[^"]*")
and then you extract what you want from the remaining string
,(?=(?:[^"]*"[^"]*")*[^"]*\z)
Regexes may not be able to count, but they can determine whether there's an odd or even number of something. After finding a comma, the lookahead asserts that, if there are any quotation marks ahead, there's an even number of them, meaning the comma is not inside a set of quotes.
This can be tweaked to handle escaped quotes if needed, though the original question didn't mention that. Also, if your regex flavor supports them, I would add atomic groups or possessive quantifiers to keep backtracking in check.