I have to write regex to match regex to match if string has dot as its first occurence.
I want 5
to match below string
.hello
The string which starts with dot
Below strings not have to match:
helo.h
I have tried like below but it wont work
/\.(.*)/g
https://regexr.com/4ibiu
you can try the following :
^\..+$
^ asserts position at start of a line
\. matches the character . literally (case sensitive)
.+ matches any character (except for line terminators)
+ Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)
$ asserts position at the end of a line
https://regex101.com/r/1WQHWA/1
Answer for my question is
https://regexr.com/4ibl0
Answer is given by #The fourth bird
Probably something like this:
/(^\..+)/
regexr.com/4ibjd
Just note that this will also match a string of all dots. If you want a word after a single dot, you can try something like this: /(^\.[a-z]+)/
try this:
[^a-z](\.(.*))
it basicly does the same as you have, and defines that there shouldn't be a a-z in front of the match
Related
I need a regular expression to grab data from a string, up to a comma. However, I need to make sure that if the string doesn't have a comma that I still grab the whole string.
Example: I need what is capitalized in the string below
"THIS IS THE FIRST PART, this is the second part"
"THIS IS THE ONLY PART"
Us the full match (typically $&) of /^[^,]*/ or use group match 1 of /^([^,]*)/
You can try this pattern:
^.+?(,|$)
Of if you really don't want to match the comma:
^.+?(?=,|$)
https://regex101.com/r/2g39yQ/1
Try
^(.*?)(?=,|$)
^ asserts position at start of a line
.*? matches any character (except for line terminators)
*? Quantifier — Matches between zero and unlimited times, as few
times as possible, expanding as needed (lazy)
Positive Lookahead (?=,|$)
Assert that the Regex below matches
1st Alternative ,
, matches the character , literally (case sensitive)
2nd Alternative $
$ asserts position at the end of a line
If only matching is needed (no capture), remove parentheses around .*?, i.e. ^.*?(?=,|$).
Here at regex101.
I would like to parse some syslog lines that they look like
Oct 20 16:34:59 artguard TTN-xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I would like to turn them into
TTN-xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
So I was wondering how the regular expression should look like that would allow me to do so, since the first part will change every day, because it is appended by the syslog.
EDIT: to avoid duplicated, I am trying to use REGEX with filebeat, where no all regex are supported as explained here
Regex101
(TTN-.*$)
Debuggex Demo
Explained
1st Capturing Group (TTN-.*$)
TTN- matches the characters TTN- literally (case sensitive)
.* matches any character (except for line terminators)
* Quantifier — Matches between zero and unlimited times, as many times as possible, giving back as needed (greedy)
$ asserts position at the end of a line
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
The regular expression TTN-\S* is probably a way of doing what you're looking for, here it is in a java-script example.
var value = "Oct 20 16:34:59 artguard TTN-xxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
var matches = value.match(
new RegExp("TTN-\\S*", "gi")
);
document.writeln(matches);
It works in two main parts:
The TTN- matches TTN- (obviously)
The \S* matches any character that is not a white-space, this is done as many times as possible.
Currently it is always expecting atleas a '-' after the TTN but if you repace the '-' with a '-{01}' in the regex it will expect TNN maybe a dash followed by 0-n characters that are not a white-space. You could also replace \S* with \w* to get all the letters and digits or .* to get all characters apart from end of line /n character, TNN-\S*[^\s{2}] too end the match with two spaces. Hope this was helpful.
I want to match a string not containing word "the"
The following solution looks logical to me:
^(?!.*the.*).*$
The following one (I've came across on SO) also works but I cannot understand WHY it works
^((?!the).)*$
In my view (?!the). should match a)ANY b)single character then repeatd by *, so the regex should match any string?
There is the great site I'm using for reference http://www.rexegg.com but no such example there
It's basically doing a match-any-character, and search for the string literal "the" in every position. If found, the negation cancels the match.
^ # Assert position at the beginning of a line (at beginning of the string or after a line break character)
( # Match the regular expression below and capture its match into backreference number 1
(?! # Assert that it is impossible to match the regex below starting at this position (negative lookahead)
the # Match the characters “the” literally
)
. # Match any single character that is not a line break character
)* # Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
$ # Assert position at the end of a line (at the end of the string or before a line break character)
The above solution works but only if you also want to match strings not containing words with the characters the in them -- e.g., I was going there would be excluded. You need word boundaries if you want to match everything not containing the word the:
^((?!\bthe\b).)*$
or:
^(?!.*\bthe\b).*$
^((?!the).)*$
This will check at every point before consuming if there is the ahead of it.So in a string abcthe after c regex engine will see the and it will fail.But because you have ^$ anchors because the the engine could not make a complete match it will fail and not match anything.If you remove $ it will match upto abc.
I'm building a regular expression which have to extract strings from brackets. This is an example string:
((?X is parent ?Y)(?X is child ?Z))
I need to get strings: '?X is parent ?Y' and also '?X is child ?Z'. This is what I've created yet:
^(\((.*?)\))+$
The problem is that it matches only the string in the second bracket. Could anybody help me to improve the expression so that it matches both strings in brackets?
Note: brackets can contain any content, like ((AAA)(BBB)). In this case 'AAA' and 'BBB' should be matched.
Thanks forward.
Based on your comments, it seems that you just want to match anything inside the brackets, for that you can use:
String Sample1 = "((something)(world)(example))";
Pattern regex = Pattern.compile("\\(?\\((.*?)\\)\\)?");
Matcher regexMatcher = regex.matcher(Sample1);
while (regexMatcher.find()) {
System.out.print(regexMatcher.group(1));
// something world example
}
Demo
Regex Explanation
Match the character “(” literally «\(?»
Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
Match the character “(” literally «\(»
Match the regular expression below and capture its match into backreference number 1 «(.*?)»
Match any single character that is not a line break character «.*?»
Between zero and unlimited times, as few times as possible, expanding as needed (lazy) «*?»
Match the character “)” literally «\)»
Match the character “)” literally «\)?»
Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
This seems to work:
Pattern.compile("[\\(]{0,1}(\\((.*?)\\))")
Thanks all for replies and comments.
I'm really struggling to put a label on this, which is probably why I was unable to find what I need through a search.
I'm looking to match the following:
Auto Reply
Automatic Reply
AutomaticReply
The platform that I'm using doesn't allow for the specification of case-insensitive searches. I tried the following regular expression:
.*[aA]uto(?:matic)[ ]*[rR]eply.*
Thinking that (?:matic) would cause my expression to match Auto or Automatic. However, it is only matching Automatic.
What am I doing wrong?
What is the proper terminology here?
This is using Perl for the regular expression engine (I think that's PCRE but I'm not sure).
(?:...) is to regex patterns as (...) is to arithmetic: It simply overrides precedence.
ab|cd # Matches ab or cd
a(?:b|c)d # Matches abd or acd
A ? quantifier is what makes matching optional.
a? # Matches a or an empty string
abc?d # Matches abcd or abd
a(?:bc)?d # Matches abcd or ad
You want
(?:matic)?
Without the needless leading and trailing .*, we get the following:
/[aA]uto(?:matic)?[ ]*[rR]eply/
As #adamdc78 points out, that matches AutoReply. This can be avoided as using the following:
/[aA]uto(?:matic[ ]*|[ ]+)[rR]eply/
or
/[aA]uto(?:matic|[ ])[ ]*[rR]eply/
This should work:
/.*[aA]uto(?:matic)? *[rR]eply/
you were simply missing the ? after (?:matic)
[Aa]uto(?:matic ?| )[Rr]eply
This assumes that you do not want AutoReply to be a valid hit.
You're just missing the optional ("?") in the regex. If you're looking to match the entire line after the reply, then including the .* at the end is fine, but your question didn't specify what you were looking for.
You can use this regex with line start/end anchors:
^[aA]uto(?:matic)? *[rR]eply$
Explanation:
^ assert position at start of the string
[aA] match a single character present in the list below
aA a single character in the list aA literally (case sensitive)
uto matches the characters uto literally (case sensitive)
(?:matic)? Non-capturing group
Quantifier: Between zero and one time, as many times as possible, giving back as needed
[greedy]
matic matches the characters matic literally (case sensitive)
* matches the character literally
Quantifier: Between zero and unlimited times, as many times as possible, giving back
as needed [greedy]
[rR] match a single character present in the list below
rR a single character in the list rR literally (case sensitive)
eply matches the characters eply literally (case sensitive)
$ assert position at end of the string
Slightly different. Same result.
m/([aA]uto(matic)? ?[rR]eply)/
Tested Against:
Some other stuff....
Auto Reply
Automatic Reply
AutomaticReply
Now some similar stuff that shouldn't match (auto).