This question already has answers here:
How do I match any character across multiple lines in a regular expression?
(26 answers)
Closed 4 years ago.
I have some confusion in Regex so I need help.my question is I am using the following Regex to prevent string should not start with some character and should not contain angular bracket.this regex also preventing next line as well so can u help me to modify it according to my need.
^(?![#=+*-])(?!.*[<>]).*$
Thanks
working example-->https://regex101.com/r/5GZQl7/1
The problem with your regex is that . does not match line endings, so as soon as you put a new line in there, the regex does not match.
Ideally, we want it to match everything, including line endings. What syntax can match everything? One way to do this is to use complementing character sets. \s matches all the whitespace, \S matches all the non-whitespace, so [\s\S] will match everything!
Replace all your .s with [\s\S]!
Demo
Related
This question already has answers here:
JavaScript: how to use a regular expression to remove blank lines from a string?
(5 answers)
Closed 2 years ago.
How can I remove the line spaces but without remove the structure of the next string.
P0:::inicial
P1:::pregunta
P2:::pregunta
P3:::pregunta
R1:::respuesta
R2:::respuesta
R3:::respuesta
R4:::respuesta
R5:::respuesta
R6:::respuesta
R7:::respuesta
R8:::respuesta
R9:::respuesta
C1:::cotizacion
C2:::cotizacion
C3:::cotizacion
A1:::agregar
A2:::agregar
<------ I want delete this spaces.
C4:::cotizacion
I try using regex but I have problems when the regex and replace remove all the spaces on my string but I only want delete the spaces without information.
In try some like this:
replace(/[\r\n]+/g, " ");
You may use this regex with anchor and MULTILINE flag:
.replace(/^[ \t]*[\r\n]+/gm, "")
RegEx Demo
MULTILINE or m mode makes ^ match start of each line.
^: matches start of a line
[ \t]*: Match 0 or more spaces or tabs
[\r\n]+: Match 1+ line break characters \r or \n
This question already has answers here:
Learning Regular Expressions [closed]
(1 answer)
Match empty string, comma, hyphen or underscore once using regex
(2 answers)
Closed 4 years ago.
I have a requirement to do a field validation using regEx. The requirement is not to have any special characters. It is working for me for a single white space, but not for multiple white spaces. It does not work if there is a white space at the beginning. Can you please help me with this?
This is what I used:
^(\w+ ?)*$
You might be looking for
^[\w ]*$
The ^ and $ are anchors for the start/end of the string, the [...] is called a character class and would allow only [A-Za-z0-9_ ]. The * is a quantifier and means zero or more times, thus the expression would also allow an empty string. If this is not what you want, change it to + instead of the *. Please note that this would also allow a string with only spaces (it really depends on what you want).
This question already has an answer here:
Reference - What does this regex mean?
(1 answer)
Closed 5 years ago.
For the following regex expression:
var regex = new RegExp("^(www\\.)?[0-9A-Za-z-\\.#:%_\+~#=]+(\\.[a-zA-Z]{2,})+(/.*)?(\\?.*)?");
I don't understand why the string "www.goo gle.com" passes the regex test. When I did this:
var regex = new RegExp("^(www\\.)?[0-9A-Za-z-\\.#:%_\+~#=]+(\\.[a-zA-Z]{2,})+(/.*)?(\\?.*)?$");
i.e. adding $ in the end of the regex string prevents the above string passing, which is what I would want.
I tried finding a "simulator" online to help me figure out how the regex is matching but couldn't find much help.
www.goo gle.com passes the test since, www. is matched by [0-9A-Za-z-\\.#:%_\+~#=]+ and
goo is matched by (\.[a-zA-Z]{2,})+. In contrast, (www\\.)?, and the last two groups are optional, so the regex is satisfied even if they are not matched, hence there's no need to further match gle.com.
By adding $, the regex no longer matches, since the space is not matched by any of the subexpressions.
This question already has answers here:
Matching a Forward Slash with a regex
(9 answers)
Closed 6 years ago.
How do I make a Slash able to be used in this Metachar String:
/#(\w+)\b/gi
That is supposed to find the "Text"(#text) This is a test #Text I agree
And it does. But now I wan't the same thing for somthing that uses a
/
You need to escape the slash so it is not interpreted as denoting special meaning. Escaping means prefixing with a backslash, so you just need two together. Adapting your existing example:
/#([\w\/]+)\b/gi
You're now allowing alphanumeric and slash characters (hence the need for a "range" of characters, denoted by square brackets.)
This one will do it: Try:(will match /Text)
/\/(\w+)\b/gi
This question already has answers here:
How to use JavaScript regex over multiple lines?
(8 answers)
Closed 7 years ago.
Considering a string like:
"#foo #foo#foo#foo #foo\n
foofoofoo\n
foo #bar"
I try for 2 days to extract the last #/# occurrence so here, the # before 'bar'. For now, i have something like this [##](?!.*[##]) which seems to work except when user insert new lines in there.
Can someone give me some tips please?
You can use this lookhahead regex:
/[##](?![\s\S]*[##])/
RegEx Demo
(?![\s\S]*[##]) is the negative lookahead that asserts there is no # or # ahead of current position in any line. [\s\S] matches any character including newline.