I know how to use Regex.Split() and Regex.Replace(); but not how to keep certain data when replacing.
if I had the following lines of text in a String[] (Split after every ;)
"
using system;
using system.blab;
using system.blab.blabity;
"
how would I loop trough and replace all 'using' to '' but match the whole line 'using (.+;)' for example.
and end up with the following (but not just Regex.replace("using", "");)
"
<using> system;
<using> system.blab;
<using> system.blab.blabity;
"
if str is your current string then
string str = #"using system;
using system.blab;
using system.blab.blabity;";
str = str.Replace("using ", "<using> ");
using parens in a Regex instructs the engine to store that value as a group. then when you call Replace, you can reference groups with $n, where n is the number of the group. I haven't tested this, but something like this:
Regex.Replace(input, #"^using( .+;)$", "$1");
Read here for more info
This should get you pretty close. You should use a named group for every logical item you're trying to match. In this instance, you're trying to match everything that is not the string "using". You can then use the notation ${yourGroupName} to reference the match in the replacement string. I wrote a tool called RegexPixie that will show you live matching of your content as you type so you can see what works and what doesn't work.
//the named group has the name "everythingElse"
var regex = new Regex(#"using(?<everythingElse>[^\r\n]+)");
var content = new string [] { /* ... */ };
for(int i = 0; i < content[i]; i++)
{
content[i] = regex.Replace(content[i], "${everythingElse}");
}
This combines 2 of the answers. It wraps word boundaries \b around using to perform a whole words only search and then captures the regex in a back-reference $1
string str = #"using system;
using system.blab;
using system.blab.blabity;";
str = Regex.Replace(str, #"\b(using)\b", "<$1>");
Related
I just want to replace a portion of a string only if matches the given text.
My use case is as follows:
var text = "<wd:response><wd:response-data></wd:response-data></wd:response >";
string result = text.Replace("wd:response", "response");
/*
* expecting the below text
<response><wd:response-data></wd:response-data></response>
*
*/
I followed the following answers:
Way to have String.Replace only hit "whole words"
Regular expression for exact match of a string
But I failed to achieve what I want.
Please share your thoughts/solutions.
Sample on
https://dotnetfiddle.net/pMkO8Q
In general, you should really be parsing and manipulating XML as XML, using functions that know how XML works and what's legal in the language. Regex and other naive text manipulation will often lead you into trouble.
That said, for a very simple solution to this specific problem, you can do this with two replaces:
var text = "<wd:response><wd:response-data></wd:response-data></wd:response >";
text.Replace("wd:response>", "response>").Replace("wd:response ", "response ")
(Note the spaces at the end of the parameters to the second replace.)
Alternatively use a regex similar to "wd:response\s*>"
The easiest way to achieve your result as per your .net fiddle is use the replace as below.
string result = text.Replace("wd:response>", "response>");
But proper way to achieve this is parsing using XML
You can capture the string wd-response in a capturing group and replace using Regex.Replace using the MatchEvaluator like this.
Regex explanation - <[/]?(wd:response)[\s+]?>
Match < literally
Match / optionally hence the ?
Match the string wd:response and place it in a capturing group enclosed with ()
Match one or more optional whitespace [\s+]?
Match > literally
public class Program
{
public static void Main(string[] args)
{
string text = "<wd:response><wd:response-data></wd:response-data></wd:response >";
string replacePattern = "response";
string pattern = #"<[/]?(wd:response)[\s+]?>";
string replacedPattern = Regex.Replace(text, pattern, match =>
{
// Extract the first group
Group group = match.Groups[1];
// Replace the group value with the replacePattern
return string.Format("{0}{1}{2}", match.Value.Substring(0, group.Index - match.Index), replacePattern, match.Value.Substring(group.Index - match.Index + group.Length));
});
Console.WriteLine(replacedPattern);
}
}
Outputting:
<response><wd:response-data></wd:response-data></response >
I am trying to get the regex to match only when there is one letter from A-Z followed by a = like this A=, a=, B=, currently it is picking up any number of letters before the = like hem=, ac2=. Usually ^[a-zA-Z] works just fine but its not working for this case since I'm using named capture groups
String pattern = "FL2 (77) Flashing,77,a=1.875,A=90.0,b=3.625,B=95.0,c=1.375,C=175.0,d=2.5,hem=0.5,16GA-AL,";
var regex = new Regex("(?<label>[a-zA-Z]+)=(?<value>[^,]+)");
Other ways I've tried
var regex = new Regex("(?<label>^[a-zA-Z]+)=(?<value>[^,]+)");
var regex = new Regex("(?<label>[^a-zA-Z]+)=(?<value>[^,]+)");
If you want to match l= but not word=, you need a negative look-behind assertion.
new Regex("(?<![a-zA-Z])(?<label>[a-zA-Z])=(?<value>[^,]+)")
If the string pattern you have in your question is really the "haystack" in which you're looking for "needles", a really easy way to solve the problem would be to first split the string on ,, then use RegEx. Then you can use a simpler pattern ^(?<label>[a-zA-Z])=(?<value>.+)$ on each item in the list you get from splitting the string, and only keep the matches.
It's because you have a + after [a-zA-Z], which makes it match one or more characters in that character class. If you remove the +, it will only match one character before the =.
If you want it to only match in situations where there is exactly one alphabetical character before the equals sign, you will want to add to the beginning of the regex to make sure that the character before the letter you want to match is not a letter, like this:
(?<![a-zA-Z])(?<label>[a-zA-Z])=(?<value>[^,]+)
(notice though that this only matters in the case where you don't put a ^ before [a-zA-Z], in the case where you want matches that don't start at the beginning of a line)
Have you tried
var regex = new Regex("(?<label>^[a-zA-Z]?)=(?<value>[^,]+)");
I believe the "+" means 1 or more
"?" means 0 or 1
or exactly 1 should be {1} (at least in python, not sure about C#)
var regex = new Regex("(?<label>^[a-zA-Z]{1})=(?<value>[^,]+)");
Assuming that the label is separated by a comma (which seems to be the case based on your example and code) then you can use:
^|,(?<label>[A-Za-z])=(?<value>[^,]+)
I recommend Regex.Matches over capture groups here:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
namespace Rextester
{
public class Program
{
public static void Main(string[] args)
{
string content = "FL2 (77) Flashing,77,a=1.875,A=90.0,b=3.625,B=95.0,c=1.375,C=175.0,d=2.5,hem=0.5,16GA-AL,";
const string regexPattern = "(?<=[,| ])[a-zA-Z]=([0-9|.|-])+";
string singleMatch = new Regex(regexPattern).Match(content).ToString();
Console.WriteLine(singleMatch); // a=1.875
MatchCollection matchList = Regex.Matches(content, regexPattern);
var matches = matchList.Cast<Match>().Select(match => match.Value).ToList();
Console.WriteLine(string.Join(", ", matches)); // a=1.875, A=90.0, b=3.625, B=95.0, c=1.375, C=175.0, d=2.5
}
}
}
I want to extract only those words within double quotes. So, if the content is:
Would "you" like to have responses to your "questions" sent to you via email?
The answer must be
you
questions
Try this regex:
\"[^\"]*\"
or
\".*?\"
explain :
[^ character_group ]
Negation: Matches any single character that is not in character_group.
*?
Matches the previous element zero or more times, but as few times as possible.
and a sample code:
foreach(Match match in Regex.Matches(inputString, "\"([^\"]*)\""))
Console.WriteLine(match.ToString());
//or in LINQ
var result = from Match match in Regex.Matches(line, "\"([^\"]*)\"")
select match.ToString();
Based on #Ria 's answer:
static void Main(string[] args)
{
string str = "Would \"you\" like to have responses to your \"questions\" sent to you via email?";
var reg = new Regex("\".*?\"");
var matches = reg.Matches(str);
foreach (var item in matches)
{
Console.WriteLine(item.ToString());
}
}
The output is:
"you"
"questions"
You can use string.TrimStart() and string.TrimEnd() to remove double quotes if you don't want it.
I like the regex solutions. You could also think of something like this
string str = "Would \"you\" like to have responses to your \"questions\" sent to you via email?";
var stringArray = str.Split('"');
Then take the odd elements from the array. If you use linq, you can do it like this:
var stringArray = str.Split('"').Where((item, index) => index % 2 != 0);
This also steals the Regex from #Ria, but allows you to get them into an array where you then remove the quotes:
strText = "Would \"you\" like to have responses to your \"questions\" sent to you via email?";
MatchCollection mc = Regex.Matches(strText, "\"([^\"]*)\"");
for (int z=0; z < mc.Count; z++)
{
Response.Write(mc[z].ToString().Replace("\"", ""));
}
I combine Regex and Trim:
const string searchString = "This is a \"search text\" and \"another text\" and not \"this text";
var collection = Regex.Matches(searchString, "\\\"(.*?)\\\"");
foreach (var item in collection)
{
Console.WriteLine(item.ToString().Trim('"'));
}
Result:
search text
another text
Try this (\"\w+\")+
I suggest you to download Expresso
http://www.ultrapico.com/Expresso.htm
I needed to do this in C# for parsing CSV and none of these worked for me so I came up with this:
\s*(?:(?:(['"])(?<value>(?:\\\1|[^\1])*?)\1)|(?<value>[^'",]+?))\s*(?:,|$)
This will parse out a field with or without quotes and will exclude the quotes from the value while keeping embedded quotes and commas. <value> contains the parsed field value. Without using named groups, either group 2 or 3 contains the value.
There are better and more efficient ways to do CSV parsing and this one will not be effective at identifying bad input. But if you can be sure of your input format and performance is not an issue, this might work for you.
Slight improvement on answer by #ria,
\"[^\" ][^\"]*\"
Will recognize a starting double quote only when not followed by a space to allow trailing inch specifiers.
Side effect: It will not recognize "" as a quoted value.
I have a multiline string (from a txt-file using ReadAllText).
the string looks like this:
R;0035709310000026542510X0715;;;
R;0035709310000045094410P1245;;;
R;0035709310000026502910Z1153;;;
I want to put in a ";" in each line on place 22, so it looks like this:
R;00357093100000265425;10X0715;;;
R;00357093100000450944;10P1245;;;
R;00357093100000265029;10Z1153;;;
The multiline string always contain the samme amount of data but not always 3 lines - sometimes more lines.
How do I make this? Please show some code.
Thanks alot :-)
Best regards
Bent
Try this ...
using System.IO;
using System.Linq;
var lines = File.ReadAllLines("data.txt");
var results = lines.Select(x => x.Insert(22, ";"));
Step 1, don't use ReadAllText(). Use ReadAllLines() instead.
string[] myLinesArray = File.ReadAllLines(...);
Step 2, replace all lines (strings) with the changed version.
for(int i = 0; i < myLinesArray.Length; i++)
myLinesArray[i] = myLinesArray[i].Insert(22, ";");
Step 3, Use WriteAllLines()
try this
string s ="R;0035709310000026542510X0715;;;";
s = s.Insert(22,";");
Console.Write(s);
or use Regex
string s =#"R;0035709310000026542510X0715;;;
R;0035709310000045094410P1245;;;
R;0035709310000026502910Z1153;;;";
string resultString = Regex.Replace(s, "^.{22}", "$0;", RegexOptions.IgnoreCase | RegexOptions.Multiline);
Console.Write(resultString);
I think it would be better to read the source file line by line and modify the line as you go.
You could build up your new file in a StringBuilder or, if is large,
write it to a new file, used to replace the source at the end.
Something like this,
using System.IO;
string tempFileName = Path.GetTempFileName();
using (StreamWriter target = File.CreateText(tempFileName))
{
using(StreamReader source = file.OpenText("YourSourceFile.???"))
{
while (source.Peek() >= 0)
{
target.WriteLine(source.ReadLine().Insert(22, ";"));
}
}
}
File.Delete("YourSourceFile.???");
File.Move(tempFileName, "YourSourceFile.???");
This approach becomes is especially appropriate for large files since it avoids loading all the data into memory at once but the performance will be good for all but very large files or, I guess, if the lines were very (very) long.
As suggested, you can use the Insert method to achieve your goal.
If your file contains a lot of lines and you need to work on 1 line at a time, you might also consider reading it line by line from a TextReader.
You could go with Regex:
myString = Regex.Replace(myString, #"(^.{22})", #"\1;", RegexOptions.Multiline);
Explanation:
you have 3 string arguments:
1st one is the input
2nd is the pattern
3rd is the replacement string
In the pattern:
() is a capturing group: you can call it in the replacement string with \n, n being the 1-based index of the capturing group in the pattern. In this case, \1 is whatever matched "(^.{22})"
"^" is the beginning of a line (because we set the multiline options, otherwise it would be the beginning of the input string)
"." matches any character
{22} means you want preceeding pattern (in this case ".", any character) 22 times
So what that means is:
"in any line with 22 characters or more, replace the 22 first characters by those same 22 characters plus ";"
Sorry guys, it seems like I didn't explain my question clearly. Please allow me to rephrase my question again.
I use WebClient to download the whole webpage and I got the content as a string
"
.......
.....
var picArr ="/d/manhua/naruto/516/1.png|/d/manhua/naruto/516/2.png|/d/manhua/naruto/516/3.png|/d/manhua/naruto/516/4.png|/d/manhua/naruto/516/5.png|/d/manhua/naruto/516/6.png|/d/manhua/naruto/516/7.png|/d/manhua/naruto/516/8.png|/d/manhua/naruto/516/9.png|/d/manhua/naruto/516/10.png|/d/manhua/naruto/516/11.png|/d/manhua/naruto/516/12.png|/d/manhua/naruto/516/13.png|/d/manhua/naruto/516/14.png|/d/manhua/naruto/516/15.png|/d/manhua/naruto/516/16.png"
......
";
in this content, I want to get only one line which is
var picArr ="/d/manhua/naruto/516/1.png|/d/manhua/naruto/516/2.png|/d/manhua/naruto/516/3.png|/d/manhua/naruto/516/4.png|/d/manhua/naruto/516/5.png|/d/manhua/naruto/516/6.png|/d/manhua/naruto/516/7.png|/d/manhua/naruto/516/8.png|/d/manhua/naruto/516/9.png|/d/manhua/naruto/516/10.png|/d/manhua/naruto/516/11.png|/d/manhua/naruto/516/12.png|/d/manhua/naruto/516/13.png|/d/manhua/naruto/516/14.png|/d/manhua/naruto/516/15.png|/d/manhua/naruto/516/16.png"
now I want use regular expression to get this string and get the value of picArr.
my reg exp is
var picArr ="([.]*)"
I think the dot means any characters. But it doesn't work. :(
Any idea?
THanks a lot
/picArr =\"([^\"]+)\"/
If I got this right that's what you need.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
namespace ExtractFileNames
{
class Program
{
static void Main(string[] args)
{
string pageData = #"blah blah
var picArr =""/d/manhua/naruto/516/1.png|/d/manhua/naruto/516/2.png|/d/manhua/naruto/516/3.png|/d/manhua/naruto/516/4.png|/d/manhua/naruto/516/5.png|/d/manhua/naruto/516/6.png|/d/manhua/naruto/516/7.png|/d/manhua/naruto/516/8.png|/d/manhua/naruto/516/9.png|/d/manhua/naruto/516/10.png|/d/manhua/naruto/516/11.png|/d/manhua/naruto/516/12.png|/d/manhua/naruto/516/13.png|/d/manhua/naruto/516/14.png|/d/manhua/naruto/516/15.png|/d/manhua/naruto/516/16.png""
more blah decimal blah";
var match = Regex.Match(pageData, #"var\s+picArr\s*=\s*""(.*?)""");
var str = match.Groups[1].Value;
var files = str.Split('|');
foreach(var f in files)
{
Console.WriteLine(f);
}
Console.ReadLine();
}
}
}
Output:
/d/manhua/naruto/516/1.png
/d/manhua/naruto/516/2.png
/d/manhua/naruto/516/3.png
/d/manhua/naruto/516/4.png
/d/manhua/naruto/516/5.png
/d/manhua/naruto/516/6.png
/d/manhua/naruto/516/7.png
/d/manhua/naruto/516/8.png
/d/manhua/naruto/516/9.png
/d/manhua/naruto/516/10.png
/d/manhua/naruto/516/11.png
/d/manhua/naruto/516/12.png
/d/manhua/naruto/516/13.png
/d/manhua/naruto/516/14.png
/d/manhua/naruto/516/15.png
/d/manhua/naruto/516/16.png
If you just want to get the filenames, you could just do a split on the pipe:
var picArr = "/d/manhua/naruto/516/1.png|/d/manhua/naruto/516/2.png|/d/manhua/naruto/516/3.png|/d/manhua/naruto/516/4.png|/d/manhua/naruto/516/5.png|/d/manhua/naruto/516/6.png|/d/manhua/naruto/516/7.png|/d/manhua/naruto/516/8.png|/d/manhua/naruto/516/9.png|/d/manhua/naruto/516/10.png|/d/manhua/naruto/516/11.png|/d/manhua/naruto/516/12.png|/d/manhua/naruto/516/13.png|/d/manhua/naruto/516/14.png|/d/manhua/naruto/516/15.png|/d/manhua/naruto/516/16.png";
var splitPics = picArr.Split('|');
foreach (var pic in splitPics)
{
Console.WriteLine(pic);
}
It looks like you want the value of the string literal in your snippet, "/d/manhua/naruto/516/1.png|..."
Get rid of the square brackets. "." matches any character just as it is, without brackets. Square brackets are for matching a limited set of characters: For example, you'd use "[abc]" to match any "a", "b", or "c".
It looks like the brackets have the effect of escaping the ".", a feature I hadn't known about (or forgot, sometime in the Ordovician). But I tested the regex as you have it with the string value replaced with a series of dots, and the regex matched. It's being treated as a literal "." character, which you would more likely try to match with a backslash escape: "\."
So just get rid of the brackets and it should work. It works in VS2008 for me.