We are trying to replace all matching patterns (regex) in a string builder with their respective "groups".
Firstly, we are trying to find the count of all occurrences of that pattern and loop through them (count - termination condition). For each match we are assigning the match object and replace them using their respective groups.
Here only the first occurrence is replaced and the other matches are never replaced.
*str* - contains the actual string
Regex - ('.*')\s*=\s*(.*)
To match pattern:
'nam_cd'=isnull(rtrim(x.nam_cd),''),
'Company'=isnull(rtrim(a.co_name),'')
Pattern : created using https://regex101.com/
*matches.Count* - gives the correct count (here 2)
String pattern = #"('.*')\s*=\s*(.*)";
MatchCollection matches = Regex.Matches(str, pattern);
StringBuilder sb = new StringBuilder(str);
Match match = Regex.Match(str, pattern);
for (int i = 0; i < matches.Count; i++)
{
String First = String.Empty;
Console.WriteLine(match.Groups[0].Value);
Console.WriteLine(match.Groups[1].Value);
First = match.Groups[2].Value.TrimEnd('\r');
First = First.Trim();
First = First.TrimEnd(',');
Console.WriteLine(First);
sb.Replace(match.Groups[0].Value, First + " as " + match.Groups[1].Value) + " ,", match.Index, match.Groups[0].Value.Length);
match = match.NextMatch();
}
Current output:
SELECT DISTINCT
isnull(rtrim(f.fleet),'') as 'Fleet' ,
'cust_clnt_id' = isnull(rtrim(x.cust_clnt_id),'')
Expected output:
SELECT DISTINCT
isnull(rtrim(f.fleet),'') as 'Fleet' ,
isnull(rtrim(x.cust_clnt_id),'') as 'cust_clnt_id'
A regex solution like this is too fragile. If you need to parse any arbitrary SQL, you need a dedicated parser. There are examples on how to parse SQL properly in Parsing SQL code in C#.
If you are sure there are no "wild", unbalaned ( and ) in your input, you may use a regex as a workaround, for a one-off job:
var result = Regex.Replace(s, #"('[^']+')\s*=\s*(\w+\((?>[^()]+|(?<o>\()|(?<-o>\)))*\))", "\n $2 as $1");
See the regex demo.
Details
('[^']+') - Capturing group 1 ($1): ', 1 or more chars other than ' and then '
\s*=\s* - = enclosed with 0+ whitespaces
(\w+\((?>[^()]+|(?<o>\()|(?<-o>\)))*\)) - Capturing group 2 ($2):
\w+ - 1+ word chars
\((?>[^()]+|(?<o>\()|(?<-o>\)))*\) - a (...) substring with any amount of balanced (...)s inside (see my explanation of this pattern).
Related
Using regex want to remove adjacent Space near replacement Character
replacementCharcter = '-'
this._adjacentSpace = new Regex($#"\s*([\{replacementCharacter}])\s*");
MatchCollection replaceCharacterMatch = this._adjacentSpace.Matches(extractedText);
foreach (Match replaceCharacter in replaceCharacterMatch)
{
if (replaceCharacter.Success)
{
cleanedText = Extactedtext.Replace(replaceCharacter.Value, replaceCharacter.Value.Trim());
}
}
Extractedtext = - whi, - ch
cleanedtext = -whi, -ch
expected result : cleanedtext = -whi,-ch
You can use
var Extactedtext = "- whi, - ch";
var replacementCharacter = "-";
var _adjacentSpace = new Regex($#"\s*({Regex.Escape(replacementCharacter)})\s*");
var cleanedText = _adjacentSpace.Replace(Extactedtext, "$1");
Console.WriteLine(cleanedText); // => -whi,-ch
See the C# demo.
NOTE:
replacementCharacter is of type string in the code above
$#"\s*({Regex.Escape(replacementCharacter)})\s*" will create a regex like \s*-\s*, Regex.Escape() will escape any regex-special char (like +, (, etc.) correctly to be used in a regex pattern, and the whole regex simply matches (and captured into Group 1 with the capturing parentheses) the replacementCharacter enclosed with zero or more whitespaces
No need using Regex.Matches, just replace all matches if there are any, that is how Regex.Replace works.
_adjacentSpace is the compiled Regex object, to replace, just call the .Replace() method of the regex object instance
The replacement is a backreference to the Group 1 value, the - char here.
I am working on a Xamarin.Forms PCL project in C# and would like to detect all the hashtags.
I tried splitting at spaces and checking if the word begins with an # but the problem is if the post contains two spaces like "Hello #World Test" it would lose that the double space
string body = "Example string with a #hashtag in it";
string newbody = "";
foreach (var word in body.Split(' '))
{
if (word.StartsWith("#"))
newbody += "[" + word + "]";
newbody += word;
}
Goal output:
Example string with a [#hashtag] in it
I also only want it to have A-Z a-z 0-9 and _ stopping at any other character
Test #H3ll0_W0rld$%Test => Test [#H3ll0_W0rld]$%Test
Other Stack questions try to detect the string and extract it, I would like it work with it and put it back in the string without losing anything that methods such as splitting by certain characters would lose.
You can use Regex with #\w+ and $&
Explanation
# matches the character # literally (case sensitive)
\w+ matches any word character (equal to [a-zA-Z0-9_])
+ Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)
$& Includes a copy of the entire match in the replacement string.
Example
var input = "asdads sdfdsf #burgers, #rabbits dsfsdfds #sdf #dfgdfg";
var regex = new Regex(#"#\w+");
var matches = regex.Matches(input);
foreach (var match in matches)
{
Console.WriteLine(match);
}
or
var result = regex.Replace(input, "[$&]" );
Console.WriteLine(result);
Ouput
#burgers
#rabbits
#sdf
#dfgdfg
asdads sdfdsf [#burgers], [#rabbits] dsfsdfds [#sdf] [#dfgdfg]
Updated Demo here
Another Example
Use a regular expression: \#\w*
string pattern = "\#\w*";
Regex rgx = new Regex(pattern, RegexOptions.IgnoreCase);
MatchCollection matches = rgx.Matches(input);
I have a string
string str = "I am fine. How are you? You need exactly 4 pieces of sandwiches. Your ADAST Count is 5. Okay thank you ";
What I want is, get the ADAST count value. For the above example, it is 5.
The problem here is, the is after the ADAST Count. It can be is or =. But there will the two words ADAST Count.
What I have tried is
var resultString = Regex.Match(str, #"ADAST\s+count\s+is\s+\d+", RegexOptions.IgnoreCase).Value;
var number = Regex.Match(resultString, #"\d+").Value;
How can I write the pattern which will search is or = ?
You may use
ADAST\s+count\s+(?:is|=)\s+(\d+)
See the regex demo
Note that (?:is|=) is a non-capturing group (i.e. it is used to only group alternations without pushing these submatches on to the capture stack for further retrieval) and | is an alternation operator.
Details:
ADAST - a literal string
\s+ - 1 or more whitespaces
count - a literal string
\s+ - 1 or more whitespaces
(?:is|=) - either is or =
\s+ - 1 or more whitespaces
(\d+) - Group 1 capturing one or more digits
C#:
var m = Regex.Match(s, #"ADAST\s+count\s+(?:is|=)\s+(\d+)", RegexOptions.IgnoreCase);
if (m.Success) {
Console.Write(m.Groups[1].Value);
}
I have a string to parse. First I have to check if string contains special pattern:
I wanted to know if there is substrings which starts with "$(",
and end with ")",
and between those start and end special strings,there should not be
any white-empty space,
it should not include "$" character inside it.
I have a little regex for it in C#
string input = "$(abc)";
string pattern = #"\$\(([^$][^\s]*)\)";
Regex rgx = new Regex(pattern, RegexOptions.IgnoreCase);
MatchCollection matches = rgx.Matches(input);
foreach (var match in matches)
{
Console.WriteLine("value = " + match);
}
It works for many cases but failed at input= $(a$() , which inside the expression is empty. I wanted NOT to match when input is $().[ there is nothing between start and end identifiers].
What is wrong with my regex?
Note: [^$] matches a single character but not of $
Use the below regex if you want to match $()
\$\(([^\s$]*)\)
Use the below regex if you don't want to match $(),
\$\(([^\s$]+)\)
* repeats the preceding token zero or more times.
+ Repeats the preceding token one or more times.
Your regex \(([^$][^\s]*)\) is wrong. It won't allow $ as a first character inside () but it allows it as second or third ,, etc. See the demo here. You need to combine the negated classes in your regex inorder to match any character not of a space or $.
Your current regex does not match $() because the [^$] matches at least 1 character. The only way I can think of where you would have this match would be when you have an input containing more than one parens, like:
$()(something)
In those cases, you will also need to exclude at least the closing paren:
string pattern = #"\$\(([^$\s)]+)\)";
The above matches for example:
abc in $(abc) and
abc and def in $(def)$()$(abc)(something).
Simply replace the * with a + and merge the options.
string pattern = #"\$\(([^$\s]+)\)";
+ means 1 or more
* means 0 or more
I need to match the following strings and returns the values as groups:
abctic
abctac
xyztic
xyztac
ghhtic
ghhtac
Pattern is wrote with grouping is as follows:
(?<arch>[abc,xyz,ghh])(?<flavor>[tic,tac]$)
The above returns only parts of group names. (meaning match is not correct).
If I use * in each sub pattern instead of $ at the end, groups are correct, but that would mean that abcticff will also match.
Please let me know what my correct regex should be.
Your pattern is incorrect because a pipe symbol | is used to specify alternate matches, not a comma in brackets as you were using, i.e., [x,y].
Your pattern should be: ^(?<arch>abc|xyz|ghh)(?<flavor>tic|tac)$
The ^ and $ metacharacters ensures the string matches from start to end. If you need to match text in a larger string you could replace them with \b to match on a word boundary.
Try this approach:
string[] inputs = { "abctic", "abctac", "xyztic", "xyztac", "ghhtic", "ghhtac" };
string pattern = #"^(?<arch>abc|xyz|ghh)(?<flavor>tic|tac)$";
foreach (var input in inputs)
{
var match = Regex.Match(input, pattern);
if (match.Success)
{
Console.WriteLine("Arch: {0} - Flavor: {1}",
match.Groups["arch"].Value,
match.Groups["flavor"].Value);
}
else
Console.WriteLine("No match for: " + input);
}