Am reading a text file that contains words, numbers and special characters, I want to remove certain special characters like: [](),'
I have this code but it is not working !
using (var reader = new StreamReader ("C://Users//HP//Documents//result2.txt")) {
string line = reader.ReadToEnd ();
Regex rgx = new Regex ("[^[]()',]");
string res = rgx.Replace (line, "");
Message1.text = res;
}
what am I missing, thanks
Some of the characters in your Regex, specifically [ ] ( ) ^, hold special meaning in Regex and in order to use them literally they must be escaped.
Use the following properly escaped Regex:
Regex rgx = new Regex (#"[\^\[\]\(\)',]");
Note that it is necessary to use the # verbatim string, because we don't want to escape these characters from the string, only from the Regex.
Alternatively, double escape the backslashes:
Regex rgx = new Regex ("[\\^\\[\\]\\(\\)',]");
But that's less readable in this case.
You could skip Regex and just maintain a list of characters you want to remove and then replace the old fashioned way:
string[] specialCharsToRemove = new [] { "[", "]", "(", ")", "'", "," };
using (var reader = new StreamReader ("C://Users//HP//Documents//result2.txt"))
{
string line = reader.ReadToEnd();
foreach(string s in specialCharsToRemove)
{
line = line.Replace(s, string.Empty);
}
Message1.text = res;
}
Ideally this would be in its own method, something like this:
private static string RemoveCharacters(string input, string[] specialCharactersToRemove)
{
foreach(string s in specialCharactersToRemove)
{
input = input.Replace(s, string.Empty);
}
return input;
}
I made a fiddle here
Replace them one at a time with String.Replace:
using (var reader = new StreamReader ("C://Users//HP//Documents//result2.txt"))
{
string line = reader.ReadToEnd ();
string res = line.Replace(line, "[", "");
res = res.Replace(line, "]", "");
res = res.Replace(line, "(", "");
res = res.Replace(line, ")", "");
res = res.Replace(line, "'", "");
res = res.Replace(line, ",", "");
Message1.text = res;
}
I agree with avoiding regex for this, but I would not use string.Replace multiple times, either.
Consider implementing a Replace or Remove method that accepts an array of characters to replace, and scan the input string only once. For example:
var builder = new StringBuilder();
foreach (char ch in input)
{
if (!chars.Contains(ch))
{
builder.Append(ch):
}
}
return builder.ToString();
Related
I have this data into the test text file:
behzad razzaqi xezerlooot abrizii ast
i want delete space and replace space one semicolon character,write this code in c# for that:
string[] allLines = File.ReadAllLines(#"d:\test.txt");
using (StreamWriter sw = new StreamWriter(#"d:\test.txt"))
{
foreach (string line in allLines)
{
if (!string.IsNullOrEmpty(line) && line.Length > 1)
{
sw.WriteLine(line.Replace(" ", ";"));
}
}
}
MessageBox.Show("ok");
behzad;;razzaqi;;xezerlooot;;;abrizii;;;;;ast
but i want one semicolon in space.how can i solve that?
Regex is an option:
string[] allLines = File.ReadAllLines(#"d:\test.txt");
using (StreamWriter sw = new StreamWriter(#"d:\test.txt"))
{
foreach (string line in allLines)
{
if (!string.IsNullOrEmpty(line) && line.Length > 1)
{
sw.WriteLine(Regex.Replace(line,#"\s+",";"));
}
}
}
MessageBox.Show("ok");
Use this code:
string[] allLines = File.ReadAllLines(#"d:\test.txt");
using (StreamWriter sw = new StreamWriter(#"d:\test.txt"))
{
foreach (string line in allLines)
{
string[] words = line.Split(" ", StringSplitOptions.RemoveEmptyEntries);
string joined = String.Join(";", words);
sw.WriteLine(joined);
}
}
You need to use a regular expression:
(\s\s+)
Usage
var input = "behzad razzaqi xezerlooot abrizii ast";
var pattern = "(\s\s+)";
Regex rgx = new Regex(pattern);
string result = rgx.Replace(input, ';');
You can do that with a regular expression.
using System.Text.RegularExpressions;
and:
string pattern = "\\s+";
string replacement = ";";
Regex rgx = new Regex(pattern);
sw.WriteLine(rgx.Replace(line, replacement));
This regular expression matches any series of 1 or more spaces and replaces the entire series with a semicolon.
you can try this
Regex r=new Regex(#"\s+");
string result=r.Replace("YourString",";");
\s+ is for matching all spaces. + is for one or more occurrences.
for more information on regular expression see http://www.w3schools.com/jsref/jsref_obj_regexp.asp
You should check a string length after replacement, not before ;-).
const string file = #"d:\test.txt";
var result = File.ReadAllLines(file).Select(line => Regex.Replace(line, #"\s+", ";"));
File.WriteAllLines(file, result.Where(line => line.Length > 1));
...and don't forget, that for input hello you will get ;hello;.
I am using asp.net mvc c#.This is my string
string filename = "excluder version(1). final"
I want to concatinate string with result
filename = "excluderversion1final"
How to do this? I dont want to use the javascript or jquery. Need to do it code behind
Sounds like a good candidate for Regex.Replace:
private static readonly Regex RemovalRegex = new Regex(#"\s|[().]");
...
public static string RemoveUnwantedCharacters(string input)
{
return RemovalRegex.Replace(input, "");
}
Note that this will handle all whitespace, not just the space character, and you can easily amend the regular expression to add extra bits.
If you just need to remove these three characters (since we're talking about small strings like file names), you can use regular string.Replace:
filename.Replace("{", "")
.Replace("}", "")
.Replace("(", "")
.Replace(")", "")
.Replace(".", "")
.Replace(" ", "");
Or maybe, simplifying it:
string fileName = "excluder version(1). final";
new List<string> { "{", "}", "(", ")", ".", " " }
.ForEach(character => fileName = fileName.Replace(character, ""));
You can use String.Replace Method:-
filename = filename.Replace(" ","").Replace("(","").Replace(")","").Replace(".","");
You can wrap this inside an extension method like this:-
public static class StringExtention
{
public static string RemoveUnwantedCharacters(this string s)
{
StringBuilder sb = new StringBuilder(s);
sb.Replace("(", "");
sb.Replace(")", "");
sb.Replace(" ", "");
sb.Replace(".", "");
return sb.ToString();
}
}
You can use this as: filename = filename.RemoveUnwantedCharacters();
But, since there is a possiblity of whitespaces too and not just space, I guess Regex is the best answer here as answered by #JonSkeet :)
By using regex:
string header = "excluder version(1). final";
Regex rgx = new Regex(#"\W+|\s");
string result = rgx.Replace(header, "");
I am currently trying to do a Regex Replace on a JSON string that looks like:
String input = "{\"`####`Answer_Options11\": \"monkey22\",\"`####`Answer_Options\": \"monkey\",\"Answer_Options2\": \"not a monkey\"}";
a
The goal is to find and replace all the value fields who's key field starts with `####`
I currently have this:
static Regex _FieldRegex = new Regex(#"`####`\w+" + ".:.\"(.*)\",");
static public string MatchKey(string input)
{
MatchCollection match = _encryptedFieldRegex.Matches(input.ToLower());
string match2 = "";
foreach (Match k in match )
{
foreach (Capture cap in k.Captures)
{
Console.WriteLine("" + cap.Value);
match2 = Regex.Replace(input.ToLower(), cap.Value.ToString(), #"CAKE");
}
}
return match2.ToString();
}
Now this isn't working. Naturally I guess since it picks up the entire `####`Answer_Options11\": \"monkey22\",\"`####`Answer_Options\": \"monkey\", as a match and replaces it. I want to just replace the match.Group[1] like you would for a single match on the string.
At the end of the day the JSON string needs to look something like this:
String input = "{\"`####`Answer_Options11\": \"CATS AND CAKE\",\"`####`Answer_Options\": \"CAKE WAS A LIE\",\"Answer_Options2\": \"not a monkey\"}";
Any idea how to do this?
you want a positive lookahead and a positive lookbehind :
(?<=####.+?:).*?(?=,)
the lookaheads and lookbehinds will verify that it matches those patterns, but not include them in the match. This site explains the concept pretty well.
Generated code from RegexHero.com :
string strRegex = #"(?<=####.+?:).*?(?=,)";
Regex myRegex = new Regex(strRegex);
string strTargetString = #" ""{\""`####`Answer_Options11\"": \""monkey22\"",\""`####`Answer_Options\"": \""monkey\"",\""Answer_Options2\"": \""not a monkey\""}""";
foreach (Match myMatch in myRegex.Matches(strTargetString))
{
if (myMatch.Success)
{
// Add your code here
}
}
this will match "monkey22" and "monkey" but not "not a monkey"
Working from #Jonesy's answer I got to this which works for what I wanted. It includes the .Replace on the groups that I required. The negative look ahead and behinds were very interesting but I needed to replace some of those values hence groups.
static public string MatchKey(string input)
{
string strRegex = #"(__u__)(.+?:\s*)""(.*)""(,|})*";
Regex myRegex = new Regex(strRegex, RegexOptions.IgnoreCase | RegexOptions.Multiline);
IQS_Encryption.Encryption enc = new Encryption();
int count = 1;
string addedJson = "";
int matchCount = 0;
foreach (Match myMatch in myRegex.Matches(input))
{
if (myMatch.Success)
{
//Console.WriteLine("REGEX MYMATCH: " + myMatch.Value);
input = input.Replace(myMatch.Value, "__e__" + myMatch.Groups[2].Value + "\"c" + count + "\"" + myMatch.Groups[4].Value);
addedJson += "c"+count + "{" +enc.EncryptString(myMatch.Groups[3].Value, Encoding.UTF8.GetBytes("12345678912365478912365478965412"))+"},";
}
count++;
matchCount++;
}
Console.WriteLine("MAC" + matchCount);
return input + addedJson;
}`
Thanks again to #Jonesy for the huge help.
I am wondering what would be the best way to specify an array of characters like,
{
}
[
]
and then check a string for these and if they are there, to completely remove them.
if (compiler.Parser.GetErrors().Count == 0)
{
AstNode root = compiler.Parse(phrase.ToLower());
if (compiler.Parser.GetErrors().Count == 0)
{
try
{
fTextSearch = SearchGrammar.ConvertQuery(root, SearchGrammar.TermType.Inflectional);
}
catch
{
fTextSearch = phrase;
}
}
else
{
fTextSearch = phrase;
}
}
else
{
fTextSearch = phrase;
}
string[] brackets = brackets = new string[]
{
"{",
"}",
"[",
"]"
};
string[] errorChars = errorChars = new string[]
{
"'",
"&"
};
StringBuilder sb = new StringBuilder();
string[] splitString = fTextSearch.Split(errorChars, StringSplitOptions.None);
int numNewCharactersAdded = 0;
foreach (string itm in splitString)
{
sb.Append(itm); //append string
if (fTextSearch.Length > (sb.Length - numNewCharactersAdded))
{
sb.Append(fTextSearch[sb.Length - numNewCharactersAdded]); //append splitting character
sb.Append(fTextSearch[sb.Length - numNewCharactersAdded - 1]); //append it again
numNewCharactersAdded++;
}
}
string newString = sb.ToString();
A regular expression can do this far more easily:
var result = Regex.Replace(input, #"[[\]()]", "");
Using a character set ([...]) to match anyone of the characters in it and replace with nothing. Regex.Replace will replace all matches.
Another concise way is using Enumerable.Except to get the set difference of the Chars(assuming brackets are chars):
String newString = new String(oldString.Except(brackets).ToArray());
string str = "faslkjnro(fjrmn){ferqwe}{{";
char[] separators = new []{'[', ']','{','}' };
var sb = new StringBuilder();
foreach (var c in str)
{
if (!separators.Contains(c))
{
sb.Append(c);
}
}
return sb.ToString();
How about this:
string myString = "a12{drr[ferr]vgb}rtg";
myString = myString.Replace("[", "").Replace("{", "").Replace("]", "").Replace("}", "");
You end up with:
a12drrferrvgbrtg
I don't know if I understand your problem, but you can solve your problem with this:
string toRemove = "{}[]";
string result = your_string_to_be_searched;
foreach(char c in toRemove)
result = result.Replace(c.ToString(), "");
or with an extension method
static class Extensions
{
public static string RemoveAll(this string src, string chars)
{
foreach(char c in chars)
src= src.Replace(c.ToString(), "");
return src;
}
}
With this you can use string result = your_string_to_be_searched.RemoveAll("{}[]");
string charsToRemove = #"[]{}";
string pattern = string.Format("[{0}]", Regex.Escape(charsToRemove));
var result = Regex.Replace(input, pattern, "");
The primary advantage of this over some of the other similar answers is that you aren't bothered with determining which characters need to be escaped in RegEx; you can let the library take care of that for you.
You can do this in a pretty compact fashion like this:
string s = "ab{c[d]}";
char[] ca = new char[] {'{', '}', '[', ']'};
Array.ForEach(ca, e => s = s.Replace(e.ToString(), ""));
Or this:
StringBuilder s = new StringBuilder("ab{c[d]}");
char[] ca = new char[] {'{', '}', '[', ']'};
Array.ForEach(ca, e => s.Replace(e.ToString(), ""));
Taken from this answer: https://stackoverflow.com/a/12800424/1498669
Just use .Split() with the char[] of your desired removeables and recapture it with .Join() or .Concat()
char[] delChars = "[]{}<>()".ToCharArray();
string input = "some (crazy) string with brac[et]s in{si}de";
string output = string.Join(string.Empty, input.Split(delChars));
//or
string output = string.Concat(input.Split(delChars));
References:
https://learn.microsoft.com/en-us/dotnet/csharp/how-to/parse-strings-using-split
https://learn.microsoft.com/en-us/dotnet/csharp/how-to/concatenate-multiple-strings#code-try-4
what is the efficient mechanism to remove 2 or more white spaces from a string leaving single white space.
I mean if string is "a____b" the output must be "a_b".
You can use a regular expression to replace multiple spaces:
s = Regex.Replace(s, " {2,}", " ");
Something like below maybe:
var b=a.Split(new char[] {' '}, StringSplitOptions.RemoveEmptyEntries);
var noMultipleSpaces = string.Join(" ",b);
string tempo = "this is a string with spaces";
RegexOptions options = RegexOptions.None;
Regex regex = new Regex(#"[ ]{2,}", options);
tempo = regex.Replace(tempo, #" ");
You Can user this method n pass your string value as argument
you have to add one namespace also using System.Text.RegularExpressions;
public static string RemoveMultipleWhiteSpace(string str)
{
// A.
// Create the Regex.
Regex r = new Regex(#"\s+");
// B.
// Remove multiple spaces.
string s3 = r.Replace(str, #" ");
return s3;
}