In C#, how would I capture the integer value in the URL like:
/someBlah/a/3434/b/232/999.aspx
I need to get the 999 value from the above url.
The url HAS to have the /someBlah/ in it.
All other values like a/3434/b/232/ can be any character/number.
Do I have escape for the '/' ?
Try the following
var match = Regex.Match(url,"^http://.*someblah.*\/(\w+).aspx$");
if ( match.Success ) {
string name = match.Groups[1].Value;
}
You didn't specify what names could appear in front of the ASPX file. I took the simple approach of using the \w regex character which matches letters and digits. You can modify it as necessary to include other items.
You are effectively getting the file name without an extension.
Although you specifically asked for a regular expression, unless you are in a scenario where you really need to use one, I'd recommend that you use System.IO.Path.GetFileNameWithoutExtension:
Path.GetFileNameWithoutExtension(Context.Request.FilePath)
^(?:.+/)*(?:.+)?/someBlah/(?:.+/)*(.+)\.aspx$
This is a bit exhaustive, but it can handle scenarios where /someBlah/ does not have to be at the beginning of the string.
The ?: operator implies a non-capturing group, which may or may not be supported by your RegEx flavor.
Regex regex = new Regex("^http://.*someBlah.*/(\\d+).aspx$");
Match match = regex.Match(url);
int result;
if (match.Success)
{
int.TryParse(match.Groups[1].Value, out result);
}
Using \d rather than \w ensures that you only match digits, and unless the ignore case flag is set the capitalisation of someBlah must be correct.
Related
I'm trying to find a regexp that only matches strings if they don't contain a dot, e.g. it matches stackoverflow, 42abc47 or a-bc-31_4 but doesn't match: .swp, stackoverflow or test..
^[^.]*$
or
^[^.]+$
Depending on whether you want to match empty string. Some applications may implicitly supply the ^ and $, in which case they'd be unnecessary. For example: the HTML5 input element's pattern attribute.
You can find a lot more great information on the regular-expressions.info site.
Use a regex that doesn't have any dots:
^[^.]*$
That is zero or more characters that are not dots in the whole string. Some regex libraries I have used in the past had ways of getting an exact match. In that case you don't need the ^ and $. Having a language in your question would help.
By the way, you don't have to use a regex. In java you could say:
!someString.contains(".");
Validation Require: First Character must be Letter and then Dot '.' is not allowed in Target String.
// The input string we are using
string input = "1A_aaA";
// The regular expression we use to match
Regex r1 = new Regex("^[A-Za-z][^.]*$"); //[\t\0x0020] tab and spaces.
// Match the input and write results
Match match = r1.Match(input);
if (match.Success)
{
Console.WriteLine("Valid: {0}", match.Value);
}
else
{
Console.WriteLine("Not Match");
}
I need a regex that will only find matches where the entire string matches my query.
For instance if I do a search for movies with the name "Red October" I only want to match on that exact title (case insensitive) but not match titles like "The Hunt For Red October". Not quite sure I know how to do this. Anyone know?
Thanks!
Try the following regular expression:
^Red October$
By default, regular expressions are case sensitive. The ^ marks the start of the matching text and $ the end.
Generally, and with default settings, ^ and $ anchors are a good way of ensuring that a regex matches an entire string.
A few caveats, though:
If you have alternation in your regex, be sure to enclose your regex in a non-capturing group before surrounding it with ^ and $:
^foo|bar$
is of course different from
^(?:foo|bar)$
Also, ^ and $ can take on a different meaning (start/end of line instead of start/end of string) if certain options are set. In text editors that support regular expressions, this is usually the default behaviour. In some languages, especially Ruby, this behaviour cannot even be switched off.
Therefore there is another set of anchors that are guaranteed to only match at the start/end of the entire string:
\A matches at the start of the string.
\Z matches at the end of the string or before a final line break.
\z matches at the very end of the string.
But not all languages support these anchors, most notably JavaScript.
I know that this may be a little late to answer this, but maybe it will come handy for someone else.
Simplest way:
var someString = "...";
var someRegex = "...";
var match = Regex.Match(someString , someRegex );
if(match.Success && match.Value.Length == someString.Length){
//pass
} else {
//fail
}
Use the ^ and $ modifiers to denote where the regex pattern sits relative to the start and end of the string:
Regex.Match("Red October", "^Red October$"); // pass
Regex.Match("The Hunt for Red October", "^Red October$"); // fail
You need to enclose your regex in ^ (start of string) and $ (end of string):
^Red October$
If the string may contain regex metasymbols (. { } ( ) $ etc), I propose to use
^\QYourString\E$
\Q starts quoting all the characters until \E.
Otherwise the regex can be unappropriate or even invalid.
If the language uses regex as string parameter (as I see in the example), double slash should be used:
^\\QYourString\\E$
Hope this tip helps somebody.
Sorry, but that's a little unclear.
From what i read, you want to do simple string compare. You don't need regex for that.
string myTest = "Red October";
bool isMatch = (myTest.ToLower() == "Red October".ToLower());
Console.WriteLine(isMatch);
isMatch = (myTest.ToLower() == "The Hunt for Red October".ToLower());
You can do it like this Exemple if i only want to catch one time the letter minus a in a string and it can be check with myRegex.IsMatch()
^[^e][e]{1}[^e]$
I need a regex that will only find matches where the entire string matches my query.
For instance if I do a search for movies with the name "Red October" I only want to match on that exact title (case insensitive) but not match titles like "The Hunt For Red October". Not quite sure I know how to do this. Anyone know?
Thanks!
Try the following regular expression:
^Red October$
By default, regular expressions are case sensitive. The ^ marks the start of the matching text and $ the end.
Generally, and with default settings, ^ and $ anchors are a good way of ensuring that a regex matches an entire string.
A few caveats, though:
If you have alternation in your regex, be sure to enclose your regex in a non-capturing group before surrounding it with ^ and $:
^foo|bar$
is of course different from
^(?:foo|bar)$
Also, ^ and $ can take on a different meaning (start/end of line instead of start/end of string) if certain options are set. In text editors that support regular expressions, this is usually the default behaviour. In some languages, especially Ruby, this behaviour cannot even be switched off.
Therefore there is another set of anchors that are guaranteed to only match at the start/end of the entire string:
\A matches at the start of the string.
\Z matches at the end of the string or before a final line break.
\z matches at the very end of the string.
But not all languages support these anchors, most notably JavaScript.
I know that this may be a little late to answer this, but maybe it will come handy for someone else.
Simplest way:
var someString = "...";
var someRegex = "...";
var match = Regex.Match(someString , someRegex );
if(match.Success && match.Value.Length == someString.Length){
//pass
} else {
//fail
}
Use the ^ and $ modifiers to denote where the regex pattern sits relative to the start and end of the string:
Regex.Match("Red October", "^Red October$"); // pass
Regex.Match("The Hunt for Red October", "^Red October$"); // fail
You need to enclose your regex in ^ (start of string) and $ (end of string):
^Red October$
If the string may contain regex metasymbols (. { } ( ) $ etc), I propose to use
^\QYourString\E$
\Q starts quoting all the characters until \E.
Otherwise the regex can be unappropriate or even invalid.
If the language uses regex as string parameter (as I see in the example), double slash should be used:
^\\QYourString\\E$
Hope this tip helps somebody.
Sorry, but that's a little unclear.
From what i read, you want to do simple string compare. You don't need regex for that.
string myTest = "Red October";
bool isMatch = (myTest.ToLower() == "Red October".ToLower());
Console.WriteLine(isMatch);
isMatch = (myTest.ToLower() == "The Hunt for Red October".ToLower());
You can do it like this Exemple if i only want to catch one time the letter minus a in a string and it can be check with myRegex.IsMatch()
^[^e][e]{1}[^e]$
What I am trying to do is fairly simple, although I am running into difficulty. I have a string that is a url, it will have the format http://www.somedomain.com?id=someid what I want to retrive is the someid part. I figure I can use a regular expression but I'm not very good with them, this is what I tried:
Match match = Regex.Match(theString, #"*.?id=(/d.)");
I get a regex exception saying there was an error parsing the regex. The way I am reading this is "any number of characters" then the literal "?id=" followed "by any number of digits". I put the digits in a group so I could pull them out. I'm not sure what is wrong with this. If anyone could tell me what I'm doing wrong I would appreciated it, thanks!
No need for Regex. Just use built-in utilities.
string query = new Uri("http://www.somedomain.com?id=someid").Query;
var dict = HttpUtility.ParseQueryString(query);
var value = dict["id"]
You've got a couple of errors in your regex. Try this:
Match match = Regex.Match(theString, #".*\?id=(\d+)");
Specifically, I:
changed *. to .* (dot matches all non-newline chars and * means zero or more of the preceding)
added a an escape sequence before the ? because the question mark is a special charcter in regular expressions. It means zero or one of the preceding.
changed /d. to \d* (you had the slash going the wrong way and you used dot, which was explained above, instead of * which was also explained above)
Try
var match = RegEx.Match(theString, #".*\?id=(\d+)");
The error is probably due to preceding *. The * character in regex matches zero or more occurrences of previous character; so it cannot be the first character.
Probably a typo, but shortcut for digit is \d, not /d
. matches any character, you need to match one or more digits - so use a +
? is a special character, so it needs to be escaped.
So it becomes:
Match match = Regex.Match(theString, #".*\?id=(\d+)");
That being said, regex is not the best tool for this; use a proper query string parser or things will eventually become difficult to manage.
Friends,
I want to match a string like
"int lnum[];" so I am trying to match it with a pattern like this
[A-Za-z_0-9] [A-Za-z_0-9]\[\]
but it does not seem to work.
I looked up rules at http://www.mikesdotnetting.com/Article/46/CSharp-Regular-Expressions-Cheat-Sheet
string pJavaLine = "int lnum[]";
match = Regex.Match(pJavaLine, #"[A-Za-z_0-9] [A-Za-z_0-9]\[\] ", RegexOptions.IgnoreCase);
if (match.Success) {
// Finally, we get the Group value and display it.
string key = match.Groups[1].Value;
Console.WriteLine(key);
}
the match.Success returns false.
Would anybody please let me know a possible way to get this.
Each of your character classes, like [A-Za-z_0-9], matches only a single character. If you want to match more than one character, you need to add something to the end. For example, [A-Za-z_0-9]+ -- the + means 1 or more of these. You could also use * for 0 or more, or specify a range, like {2,5} for 2-5 characters.
That said, you can use this pattern to match that string:
[A-Za-z_0-9]+ [A-Za-z_0-9]+\[\]
The \w is loosely equivalent to [A-Za-z_0-9] (see link in jessehouwing's comment below), so you can probably simply use:
\w+ \w+\[\]
Check here for more info on the standard Character Classes.