I need a regex pattern which will accommodate for the following.
I get a response from a UDP server, it's a very long string and each word is separated by \, for example:
\g79g97\g879o\wot87gord\player_0\name0\g6868o\g78og89\g79g79\player_1\name1\gyuvui\yivyil\player_2\name2\g7g87\g67og9o\v78v9i7
I need the strings after \player_n\, so in the above example I would need name0, name1 and name3,
I know this is the second regex question of the day but I have the book (Mastering Regular Expressions) on order! Thank you.
UPDATE. elusive's regex pattern will suffice, and I can add the match(0) to a textbox. However, what if I want to add all the matches to the text box ?
textBox1.Text += match.Captures[0].ToString(); //this works fine.
How do I add "all" match.captures to the text box? :s sorry for being so lame, this Regex class is brand new to me .
Try this one:
\\player_\d+\\([^\\]+)
i think that this test sample can help you
string inp = #"\g79g97\g879o\wot87gord\player_0\name0\g6868o\g78og89\g79g79\player_1\name1\gyuvui\yivyil\player_2\name2\g7g87\g67og9o\v78v9i7";
string rex = #"[\w]*[\\]player_[0-9]+[\\](?<name>[A-Za-z0-9]*)\b";
Regex re = new Regex(rex);
Match mat = re.Match(inp);
for (Match m = re.Match(inp); m.Success; m = m.NextMatch())
{
Console.WriteLine(m.Groups["name"]);
}
you can take the name of the player from the m.Groups["name"]
To get only the player name, you could use:
(?<=\\player_\d+\\)[^\\]+
This (?<=\\player_\d+\\) is something called a positive look-behind. It makes sure that the actual match [^\\]+ is preceded by the expression in the parentheses.
In this case, it's even specific to only a few regex engines (.NET being among them, luckily), in that it contains a variable length expression (due to \d+). Most regex engines only support fixed-length look-behind.
In any case, look-behind is not necessarily the best approach to this problem, match groups are simpler easier to read.
Related
I currently have a regex that checks if a US State is spelled correctly
var r = new Regex(string.Format(#"\b(?:{0})\b", pattern), RegexOptions.IgnoreCase)
pattern is a pipe delimited string containing all US states.
It was working as intended today until one of the states was spelled like "Florida.." I would have liked it picked up the fact there was a fullstop character.
I found this regex that will only match letters.
^[a-zA-Z]+
How do I combine this with my current Regex or is it not possible?
I tried some variations of this but it didn't work
var r = new Regex(string.Format(#"\b^[a-zA-Z]+(?:{0})\b", pattern), RegexOptions.IgnoreCase);
EDIT: Florida.. was in my input string. My pattern string hasn't changed at all. Apologies for not being clearer.
It seems you need start of string (^) and end of string ($) anchors:
var r = new Regex(string.Format(#"^(?:{0})$", pattern), RegexOptions.IgnoreCase);
The regex above would match any string comprising a name of a state only.
You should make a replacement of the pattern variable to escape the regex special characters. One of them is the . character. Something similar to pattern.Replace(".", #"\.") but doing all the especial characters.
I believe you can't merge both patterns into one, so you would have to perform two diferent regex operations, one to split the states into a list, and a subsequent one for the validation of each item within it.
I'd rather go for something "simpler" such as
var states = input.Split('|').Select(s => new string(s.Where(char.IsLetter).ToArray()))
.Where(s => !string.IsNullOrWhiteSpace(s));
Basically don't use a regex here.
List<string> values = new List<string>() {"florida", etc.};
string input;
//is input in values, ignore case and look for any value that includes the input value
bool correct = values.Any(a =>
input.IndexOf(a, StringComparison.CurrentCultureIgnoreCase) >= 0);
This will be considerably more efficient than a regex based option. This should match florida, Florida and Florida..., etc.
Don't search for characters directly, tell regex to consume all which are not targeted specific characters such as [^\|.]+. It uses the set [ ] with the not ^ indicator says consume anything which is not a literal | or .. Hence it consumes just the text needed. Such as on
Colorado|Florida..|New Mexico
returns 3 matches of Colorado Florida and New Mexico
I am trying to figure out a regex expression for a project, and struggling here.
Here's my sample string:
[link="http://www.cnn.com"]CNN Webpage[/link]
I want to regex.replace the above example to this:
CNN Webpage
I know there is a Regex way to do this. Can anyone help?
I personally prefer using named groups when I can. As you'll see it makes the regex/code a little more maintainable/readable. This also helps with maintenance on the code as the captured groups are no longer being referenced by the index. As you probably know, the index groups will change if you change any preceding capturing groups within the regex.
The named groups will stay consistent through the lifetime of the regex unless you specifically change it.
Regex
\[link=["\u201C](?<href>[^"\u201D]+)["\u201D]\](?<title>[^\[]+)\[/link\]
Regex Demo - Note the regex is different because of the different regex engines, but the regex is equal to the one I present here.
Code
var str = "[link=\"http://www.cnn.com\"]CNN Webpage[/link] OR [link=“http://www.cnn.com”]CNN Webpage[/link]";
var regex = new Regex(#"\[link=[""\u201C](?<href>[^""\u201D]+)[""\u201D]\](?<title>[^\[]+)\[/link\]");
//The ${name} refers to a named capture group in the regex. Makes it a little more readable, and maintainable.
str = regex.Replace(str, "${title}");
Console.WriteLine(str);
Please note that the regex only supports the "smart quotes" if the quotes are used properly, to handle cases where the quotes might be reversed you'd need to do something like this:
\[link=["\u201C\u201D](?<href>[^"\u201D\u201C]+)["\u201D\u201C]\](?<title>[^\[]+)\[/link\]
Just for clarity, the example below shows where this regex would be useful. Notice the last link has the unicode characters messed up. It uses the unicode right quote (\u201D ”) on both sides of the text. This regex will parse the data, but the one at the beginning of the post will not.
var str = "[link=\"http://www.cnn.com\"]CNN Webpage[/link] OR [link=“http://www.cnn.com”]CNN Webpage[/link] OR [link=”http://www.cnn.com”]CNN Webpage[/link]";
var regex = new Regex(#"\[link=[""\u201C\u201D](?<href>[^""\u201D\u201C]+)[""\u201D\u201C]\](?<title>[^\[]+)\[/link\]");
//The ${name} refers to a named capture group in the regex. Makes it a little more readable, and maintainable.
str = regex.Replace(str, "${title}");
Use capturing groups to capture the http link and the content of [link] tag.
Regex:
\[link="([^"]*)"\]([^\[\]]*)\[\/link]
Replacement string:
$2
DEMO
\[link(="[^"]+")\]([^\[]+)\[\/link\]
Try this.Replace by <a href$1 target="_blank">$2</a>.See demo.
http://regex101.com/r/kP8uF5/18
How can I use regex to replace matching strings that do not include a specific string?
input string
Keepword mywordsecond mythirdword myfourthwordKeep
string to replace
word
exclude string
Keep
Desired out put
Keepword mysecond mythird myfourthKeep
Will there ever be more than one word in a word? If there are more than one, do you want to replace all of them? If not, this should sort you out:
Regex r = new Regex(#"\b((?:(?!Keep|word)\w)*)word((?:(?!Keep)\w)*)\b");
s1 = r.Replace(s0, "$1$2");
to explain:
First, \b((?:(?!Keep|word)\w)*) captures whatever text precedes the first occurrence of word or Keep.
The next thing it sees must be word, If it sees Keep or the end of the string instead, the match attempt immediately fails.
Then ((?:(?!Keep)\w)*)\b captures the remainder of the text in order to ensure it doesn't contain Keep.
When faced with a problem like this, most users' first impulse is to match (in the sense of consuming) only the part of the string they're interested in, using lookarounds to establish the context. It's usually much easier to write the regex so that it always moves forward through the string as it matches. You capture the parts you want to retain so you can plug them back into the result string by means of group references ($1, $2, etc.).
Given that you're using C#, you could use the lookaround approach:
Regex r = new Regex(#"(?<!Keep\w*)word(?!\w*Keep)");
s1 = r.Replace(s0, "");
But please don't. There are very few regex flavors that support unrestricted lookbehinds like .NET does, and most problems don't work so neatly as this one anyway.
string str = "Keepword mywordsecond mythirdword myfourthwordKeep";
str = Regex.Replace(str, "(?<!Keep)word", "");
And I'm going to link you to a one of good Regular Expressions Cheat sheet here
This works in notepad++:
(?<!Keep)word(?!Keep)
It uses "look ahead".
You can use negative look-behind assertion if you want to remove all "word" that are not proceeded by "Keep":
String input = "Keepword mywordsecond mythirdword myfourthwordKeep";
String pattern = "(?<!Keep)word";
String output = Regex.Replace(input, pattern, "");
I need some help on a problem.
In fact I search to check for an image type by the hexadecimal code.
string JpgHex = "FF-D8-FF-E0-xx-xx-4A-46-49-46-00";
Then I have a condition on
string.StartsWith(pngHex).
The problem is that the "x" characters presents in my "JpgHex" string can be whatever I want.
I think I need a regex to check that but I don't know how!!
Thanks a lot!
I'm not quite clear what exactly you want to do, but the dot '.' character represents any character in Regex.
So the regex "^FF-D8-FF-E0-..-..-4A-46-49-46-00" will probably do the trick. '^' = Start of input.
If you want to allow only hex chars you can use "^FF-D8-FF-E0-[0-9A-F]{2}-[0-9A-F]{2}-4A-46-49-46-00".
Like I said, I'd need a better idea of what pattern you need to match.
Here are some examples:
Regex rgx =
new Regex(#"^FF-D8-FF-E0-[a-zA-Z0-9]{2}-[a-zA-Z0-9]{2}-4A-46-49-46-00$");
rgx.IsMatch(pngHex); // is match will return a bool.
I use [a-zA-Z0-9]{2} to denote two instances of a character, caps or small or a number. So the above regex would match :
FF-D8-FF-E0-aa-zZ-4A-46-49-46-00
FF-D8-FF-E0-11-22-4A-46-49-46-00
.. etc
Based on your need change the regex accordingly so for capitals and numbers only you change to [A-Z0-9]. The {2} denotes two occurrences.
The ^ denotes the string should start with FF and $ means the string should end with 00.
Lets say you wanted to only match two numbers, so you would use \d{2}, the whole thing would look like this:
Regex rgx = new Regex(#"^FF-D8-FF-E0-\d{2}-\d{2}-4A-46-49-46-00$");
rgx.IsMatch(pngHex);
How do I know of these magical characters? Simple, there are docs everywhere. See this MSDN page for some basic regex patterns. This page shows some quantifiers, those are things like match one or more or match only one.
Cheat-sheets also come in handy.
A regex would help you; you can use the following tool to help you test and learn: -
http://derekslager.com/blog/posts/2007/09/a-better-dotnet-regular-expression-tester.ashx
I recommend you have a play because then you'll learn!
To simply match any character in place of the x, the following should work: -
"^FF-D8-FF-E0-..-..-4A-46-49-46-00$"
In C#, it would be something like this: -
var test = "FF-D8-FF-E0-AB-CD-4A-46-49-46-00";
var foo = new Regex("^FF-D8-FF-E0-..-..-4A-46-49-46-00$");
if (foo.IsMatch(test))
{
// Do magic
}
You will need to read up on regular expressions to understand some of the characters that may not look familiar, i.e. ^ and $. See http://www.regular-expressions.info/
At the moment I am trying to match patterns such as
text text date1 date2
So I have regular expressions that do just that. However, the issue is for example if users input data with say more than 1 whitespace or if they put some of the text in a new line etc the pattern does not get picked up because it doesn't exactly match the pattern set.
Is there a more reliable way for pattern matching? The goal is to make it very simple for the user to write but make it easily matchable on my end. I was considering stripping out all the whitespace/newlines etc and then trying to match the pattern with no spaces i.e. texttextdate1date2.
Anyone got any better solutions?
Update
Here is a small example of the pattern I would need to match:
FIND me#test.com 01/01/2010 to 10/01/2010
Here is my current regex:
FIND [A-Z0-9._%+-]+#[A-Z0-9.-]+\.[A-Z]{2,4} [0-9]{1,2}/[0-9]{1,2}/[0-9]{2,4} to [0-9]{1,2}/[0-9]{1,2}/[0-9]{2,4}
This works fine 90% of the time, however, if users submit this information via email it can have all different kinds of formatting and HTML I am not interested in. I am using a combination of the HtmlAgilityPack and a HTML tag removing regex to strip all the HTML from the email, but even at that I can't seem to get a match on some occassions.
I believe this could be a more parsing related question than pattern matching, but I think maybe there is a better way of doing this...
To match at least one or more whitespace characters (space, tab, newline), use:
\s+
Substitute the above wherever you have the physical space in your pattern and you should be fine.
Example of matching multiple groups in a text with multiple whitespaces and/or newlines.
var txt = "text text date1\ndate2";
var matches = Regex.Match(txt, #"([a-z]+)\s+([a-z]+)\s+([a-z0-9]+)\s+([a-z0-9]+)", RegexOptions.Singleline);
matches.Groups[n].Value with n from 1 to 4 will contain your matches.
I would split the string into a string array and match each resulting string to the necessary Regular Expression.
\b(text)[\s]+(text)[\s]+(date1)[\s]+(date2)\b
Its a nasty expression but here is something that will work for the input you provided:
^(\w+)\s+([\w#.]+)\s+(\d{2}\/\d{2}\/\d{4})[^\d]+(\d{2}\/\d{2}\/\d{4})$
This will work with variable amounts of whitespace between the capture groups as well.
Through ORegex you can tokenize your string and just pattern match on token sequences:
var tokens = input.Split(new[]{' ','\t','\n','\r'}, StringSplitOptions.RemoveEmptyEntries);
var oregex = new ORegex<string>("{0}{0}{1}{1}", IsText, IsDate);
var matches = oregex.Matches(tokens); //here is your subsequence tokens.
...
public bool IsText(string str)
{
...
}
public bool IsDate(string str)
{
...
}