I would like to validate my string and would need help with regex. How do I express such a string:
anything, then dash and some digits. Empty input should be ok too, if possible.
so:
[nothing] = valid
astring = valid
astring- = invalid
astring-1 = valid
astring-a = invalid
astring-a1 = invalid
You can use this regex:
^[^-]*(-[0-9]+)?$
RegEx Demo
Try this simple regex :
^*(-[0-9]+)?$
Related
I am trying to get string using RegEx; here is the string:
window.runParams = {};
window.runParams = {blablabla};
How to get the second string {blablabla}? I am using REGEX:
(?<=window.runParams = ").*(?=;)
But that gets the first string {}.
If you want to get string with braces eg: {blablabla}
window.runParams = ({\w+})
If you want to get only the string inside braces eg: blablabla
window.runParams = {(\w+)}
Value of group 1 is your result
The following pattern captures only curly brackets with word character content:
(?<=window.runParams = ){\w+}(?=;)
and will only capture:
{blablabla}
when run against the text:
window.runParams = {};
window.runParams = {blablabla};
See results here:
https://regex101.com/r/mTwA64/1
try modifying your regex so it only accepts matches with non-empty curly brackets \{.+\} such as
(?<=window\.runParams = )(\{.+\})(?=;)
...there's probably ways to simplify the regex further, depending on you problem...my guess is you don't need the lookahead/lookbehind, e.g. in the example given \{.+\} will do just fine (returns {blablabla}) ....but it really depends on the format and content of your file...also remember braces, dots etc have a special meaning in regexes so you probably would want to escape them
I'm trying to get my Dart web app to: (1) determine if a particular string matches a given regex, and (2) if it does, extract a group/segment out of the string.
Specifically, I want to make sure that a given string is of the following form:
http://myapp.example.com/#<string-of-1-or-more-chars>[?param1=1¶m2=2]
Where <string-of-1-or-more-chars> is just that: any string of 1+ chars, and where the query string ([?param1=1¶m2=2]) is optional.
So:
Decide if the string matches the regex; and if so
Extract the <string-of-1-or-more-chars> group/segment out of the string
Here's my best attempt:
String testURL = "http://myapp.example.com/#fizz?a=1";
String regex = "^http://myapp.example.com/#.+(\?)+\$";
RegExp regexp= new RegExp(regex);
Iterable<Match> matches = regexp.allMatches(regex);
String viewName = null;
if(matches.length == 0) {
// testURL didn't match regex; throw error.
} else {
// It matched, now extract "fizz" from testURL...
viewName = ??? // (ex: matches.group(2)), etc.
}
In the above code, I know I'm using the RegExp API incorrectly (I'm not even using testURL anywhere), and on top of that, I have no clue how to use the RegExp API to extract (in this case) the "fizz" segment/group out of the URL.
The RegExp class comes with a convenience method for a single match:
RegExp regExp = new RegExp(r"^http://myapp.example.com/#([^?]+)");
var match = regExp.firstMatch("http://myapp.example.com/#fizz?a=1");
print(match[1]);
Note: I used anubhava's regular expression (yours was not escaping the ? correctly).
Note2: even though it's not necessary here, it is usually a good idea to use raw-strings for regular expressions since you don't need to escape $ and \ in them. Sometimes using triple-quote raw-strings are convenient too: new RegExp(r"""some'weird"regexp\$""").
Try this regex:
String regex = "^http://myapp.example.com/#([^?]+)";
And then grab: matches.group(1)
String regex = "^http://myapp.example.com/#([^?]+)";
Then:
var match = matches.elementAt(0);
print("${match.group(1)}"); // output : fizz
Im new to regular expressions and Im trying to use RegExp on gwt Client side. I want to do a simple * matching. (say if user enters 006* , I want to match 006...). Im having trouble writing this. What I have is :
input = (006*)
input = input.replaceAll("\\*", "(" + "\\" + "\\" + "S\\*" + ")");
RegExp regExp = RegExp.compile(input).
It returns true with strings like BKLFD006* too. What am I doing wrong ?
Put a ^ at the start of the regex you're generating.
The ^ character means to match at the start of the source string only.
I think you are mixing two things here, namely replacement and matching.
Matching is used when you want to extract part of the input string that matches a specific pattern. In your case it seems that is what you want, and in order to get one or more digits that are followed by a star and not preceded by anything then you can use the following regex:
^[0-9]+(?=\*)
and here is a Java snippet:
String subjectString = "006*";
String ResultString = null;
Pattern regex = Pattern.compile("^[0-9]+(?=\\*)");
Matcher regexMatcher = regex.matcher(subjectString);
if (regexMatcher.find()) {
ResultString = regexMatcher.group();
}
On the other hand, replacement is used when you want to replace a re-occurring pattern from the input string with something else.
For example, if you want to replace all digits followed by a star with the same digits surrounded by parentheses then you can do it like this:
String input = "006*";
String result = input.replaceAll("^([0-9]+)\\*", "($1)");
Notice the use of $1 to reference the digits that where captured using the capture group ([0-9]+) in the regex pattern.
I'd like to capture the value of the Initial Catalog in this string:
"blah blah Initial Catalog = MyCat'"
I'd like the result to be: MyCat
There could or could not be spaces before and after the equal sign and there could or could not be spaces before the single quote.
Tried this and various others but no go:
/Initial Catalog\s?=\s?.*\s?\'/
Using .Net.
You need to put parentheses around the part of the string that you would like to match:
/Initial Catalog\s*=\s*(.*?)\s*'/
Also you would like to exclude as many spaces as possible before the ', so you need \s* rather than \s?. The .*? means that the extracted part of the string doesn't take those spaces, since it is now lazy.
This is a nice regex
= *(.*?) *'
Use the idea and add \s and more literal text as needed.
In C# group 1 will contain the match
string resultString = null;
try {
Regex regexObj = new Regex("= *(.*?) *'");
resultString = regexObj.Match(subjectString).Groups[1].Value;
} catch (ArgumentException ex) {
// Syntax error in the regular expression
}
Regex rgx = new Regex(#"=\s*([A-z]+)\s*'");
String result = rgx.Match(text).Groups[1].Value;
I've been checking all over the internet but really can't find any specific solution of my problem.
How do I check if a string consists of only the declared valid characters?
I want my string to consists of only 0-9, A-Z and a-z
So the string oifrmf9RWGEWRG3oi4m3ofm3mklwef-qæw should be invalid because of - and æ
while the string joidsamfoiWRGWRGmoi34m3f should be valid.
I have been using the build-in RegExp to strip the strings, but is it possible to just make it check and return a boolean false or true?
my regexp:
set pw = new regexp
pw.global = true
pw.pattern = "[^a-zA-Z0-9]"
newstring = pw.replace("iownfiwefnoi3w4mtl3.-34ø'3", "")
Thanks :)
You could do a Test which returns True or False
If( pw.Test("string") ) Then
'' Do something
End If
Try -
Dim myRegExp, FoundMatch
Set myRegExp = New RegExp
myRegExp.Pattern = "[^a-zA-Z0-9]"
FoundMatch = myRegExp.Test("iownfiwefnoi3w4mtl3.-34ø'3")
If FoundMatch is true the RegEx engine has found a character that is not a-z or A-Z or 0-9 and your string is not valid.
You could do something like:
Set match = pw.execute("iownfiwefnoi3w4mtl3.-34ø'3")
if match.count > 0 then
' your pattern matched, so it's invalid
badString = true
else
badString = false
end if
Rather than replace you can look and see if there is a match on any characters outside the whitelist. The general for each match syntax is here
[a-zA-Z0-9] works...I tried it against your string here http://gskinner.com/RegExr/?2u7c3 and here http://regexpal.com/ ...take the carrot out. I also can't remember the regex engine vbscript uses but that might have something to do with your problem. This also works...
\D?\w