match each occurrence of a dot until a single colon - regex

Take this string
bob.ted.dave.allan::james.fred: hello.dave
I need to replace each occurrence of . with # until I hit a singular ":" not stopping at the namespace '::' but just the ":"
So in the above string, the end result will be
bob#ted#dave#allan::james#fred: hello.dave
currently I have [.] which matches all dots in the string but cant get it to anchor on the single ":"


If you want a pure regex solution this can only be done with a variable-width lookbehind pattern, which is supported by only a few regex engines:
(?<!(?<!:):(?!:).*)\.
Demo: https://regex101.com/r/Crq49C/2
Or if there is always going to be a colon, you can use a positive lookahead pattern instead:
\.(?=.*(?<!:):(?!:))
Demo: https://regex101.com/r/Crq49C/3


To just anchor on a single . and not stop until seeing exactly one : I think
[.](?=.*:{1})
will work.
This does not work if there is more than one : on a line.


You can capture the entire string up until the single : with a simple character set match:
[\w\. :]+(?::{1})
Then do a replace on all of the .'s in the captured string.
Demo: https://regex101.com/r/xDfstu/1

Related

Regex expression to ignore first and last character

So I am trying to make a regex match for strings of the form:
"catalog.schema.'tablename'" .
The output I am looking for is just catalog.schema.'tablename' leaving out the quotes at the end position.
Can anyone help me out
I tried to do it with the expression
/(?!^|.$)+[^\s]/ which leaves out the end quotes but matches each character.
So I modified it to /(?!^|.$)+[^\s]+/g . This matches the whole sentence but doesn't ignore the end quote.

Depends on the data arround your string and quotationmarks may be within the string.
Why not just this: "(.*?)"
https://regex101.com/r/oaS8o0/1
To answer the question in the title you might simply use:
^.(.*)?.$
https://regex101.com/r/FxJgtW/1

You can just use
(?<=.).+(?=.)
Or, if you cannot use lookbehind:
(?!^).+(?!$)
See the regex demo #1 and regex demo #2.
Since . matches any char other than line break chars, the patterns just match any strings without their start and end chars.

If you don't want to match the first and the last character, you can just use a capture group instead of lookarounds and use the group 1 value.
The first . matches the first of (any) characters, the (.+) is a capture group that matches 1 or more characters, and the . at the end matches the last character of the string.
.(.+).
Regex demo
Or to get the text between the double quotes at the start and the end of the string using a negated character class and a capture group:
^"([^"]+)"$
Regex demo

Removing last character from a line using regex

I just started learning regex and I'm trying to understand how it possible to do the following:
If I have:
helmut_rankl:20Suzuki12
helmut1195:wasserfall1974
helmut1951:roller11
Get:
helmut_rankl:20Suzuki1
helmut1195:wasserfall197
helmut1951:roller1
I tried using .$ which actually match the last character of a string, but it doesn't match letters and numbers.
How do I get these results from the input?

You could match the whole line, and assert a single char to the right if you want to match at least a single character.
.+(?=.)
Regex demo
If you also want to match empty strings:
.*(?=.)

This will do what you want with regex's match function.
^(.*).$
Broken down:
^ matches the start of the string
( and ) denote a capturing group. The matches which fall within it are returned.
.* matches everything, as much as it can.
The final . matches any single character (i.e. the last character of the line)
$ matches the end of the line/input

Match a part of a string using regex

I have a string and would like to match a part of it.
The string is Accept: multipart/mixedPrivacy: nonePAI: <sip:4168755400#1.1.1.238>From: <sip:4168755400#1.1.1.238>;tag=5430960946837208_c1b08.2.3.1602135087396.0_1237422_3895152To: <sip:4168755400#1.1.1.238>
I want to match PAI: <sip:4168755400#
the whitespace can be a word so i would like to use .* but if i used that it matches most of the string
The example on that link is showing what i'm matching if i use the whitespace instead of .*
(PAI: <sip:)((?:\([2-9]\d{2}\)\ ?|[2-9]\d{2}(?:\-?|\ ?))[2-9]\d{2}[- ]?\d{4})#
The example on that link is showing what i'm trying to achieve with .* but it should only match PAI: <sip:4168755400#
(PAI:.*<sip:)((?:\([2-9]\d{2}\)\ ?|[2-9]\d{2}(?:\-?|\ ?))[2-9]\d{2}[- ]?\d{4})#
I tried lookaround but failing.
Any idea?
thanks

Matching the single space can be updated by using a character class matching either a space or a word character and repeat that 1 or more times to match at least a single occurrence.
Note that you don't have to escape the spaces, and in both occasions you can use an optional character class matching either a space or hyphen [ -]?
If you want the match only, you can omit the 2 capturing groups if you want to.
(PAI:[ \w]+<sip:)((?:\([2-9]\d{2}\) ?|[2-9]\d{2}[ -]?)[2-9]\d{2}[- ]?\d{4})#
Regex demo

The regex should be like
PAI:.*?(<sip:.*?#)
Explanation:
PAI:.*? find the word PAI: and after the word it can be anything (.*) but ? is used to indicate that it should match as few as possible before it found the next expression.
(<sip:.*?#) capturing group that we want the result.
<sip:.*?# find <sip: and after the word it can be anything .*? before it found #.
Example

Regex - Discard the entire string if any part of the string doesn't match the pattern

I have a comma separated string which I want to validate using a regex. What I have written is gives me a match if there a part wrong later in the string. I want to discard it completely if any part is wrong.
My regex : ^(?:[\w\.]+,{1}(?:STR|INT|REAL){1},{1}(\s*|$))+
Positive Case : Component,STR,YoungGenUse,STR,YoungGenMax,STR,OldGenUse,INT,OldGenMax,INT,PermGenUse,INT,PermGenMax,INT,MajCollCnt,INT,MinCollDur,REAL,MinCollCnt,INT,
Negative Case :
Component,STR,YoungGenUse,STR,YoungGenMax,TEST,OldGenUse,INT,OldGenMax,INT,PermGenUse,INT,PermGenMax,INT,MajCollCnt,INT,MinCollDur,REAL,MinCollCnt,INT,
For the second case, my regex gives a match for the bold portion eventhough, later there is an incorrect part (TEST). How can I modify my regex to discard the entire string?

The pattern that you tried would not match TEST in YoungGenMax,TEST because the alternatives STR|INT|REAL do not match it.
It would show until the last successful match in the repetition which would be Component,STR,YoungGenUse,STR,
You have to add the anchor at the end, outside of the repetition of the group, to indicate that the whole pattern should be followed by asserting the end of the string.
There are no spaces or dots in your string, so you might leave out \s* and use \w+ without the dot in the character class. Note that \s could also possibly match a newline.
^(?:\w+,(?:STR|INT|REAL),)+$
Regex demo
If you want to keep matching optional whitespace chars and the dot:
^(?:[\w.]+,(?:STR|INT|REAL),\s*)+$
Regex demo
Note that by repeating the group with the comma at the end, the string should always end with a comma. You can omit {1} from the pattern as it is superfluous.

your regex must keep matching until end of the string, so you must use $ to indicate end of the line:
^(?:[\w.]+,{1}(?:STR|INT|REAL){1},{1}(\s*|$))+$
Regex Demo

Apply negative look-ahead to preceeding group

I'm trying since hours to get this negative-look-ahead to work for me. It should match my string only if it's NOT followed by '/CCC'
http://refiddle.com/1xb
/(^[\w]+)(?!./CCC$)/mg
Test string:
BBB/CCC
AAA/DDD/CCC
Could someone point out why my pattern still matches the 'BBB' of the first line?

Firstly, you have to escape the / inside the regular expression.
You also have a dot that shouldn't be there and are missing a word boundary:
/(^\w+)\b(?!\/CCC$)/mg
refiddle