Replacing characters in a string with another string - c#

So what I am trying to do is as follows :
example of a string is A4PC
I am trying to replace for example any occurance of "A" with "[A4]" so I would get and similar any occurance of "4" with "[A4]"
"[A4][A4]PC"
I tried doing a normal Replace on the string but found out I got
"[A[A4]]PC"
string badWordAllVariants =
restriction.Value.Replace("A", "[A4]").Replace("4", "[A4]")
since I have two A's in a row causing an issue.
So I was thinking it would be better rather than the replace on the string I need to do it on a character per character basis and then build up a string again.
Is there anyway in Linq or so to do something like this ?

You don't need any LINQ here - String.Replace works just fine:
string input = "AAPC";
string result = input.Replace("A", "[A4]"); // "[A4][A4]PC"
UPDATE: For your updated requirements I suggest to use regular expression replace
string input = "A4PC";
var result = Regex.Replace(input, "A|4", "[A4]"); // "[A4][A4]PC"

This works well for me:
string x = "AAPC";
string replace = x.Replace("A", "[A4]");
EDIT:
Based on the updated question, the issue is the second replacement. In order to replace multiple strings you will want to do this sequentially:
var original = "AAPC";
// add arbitrary room to allow for more new characters
StringBuilder resultString = new StringBuilder(original.Length + 10);
foreach (char currentChar in original.ToCharArray())
{
if (currentChar == 'A') resultString.Append("[A4]");
else if (currentChar == '4') resultString.Append("[A4]");
else resultString.Append(currentChar);
}
string result = resultString.ToString();
You can run this routine with any replacements you want to make (in this case the letters 'A' and '4' and it should work. If you would want to replace strings the code would be similar in structure but you would need to "look ahead" and probably use a for loop. Hopefully this helps!
By the way - you want to use a string builder here and not strings because strings are static which means space gets allocated every time you loop. (Not good!)

I think this should do the trick
string str = "AA4PC";
string result = Regex.Replace(str, #"(?<Before>[^A4]?)(?<Value>A|4)(?<After>[^A4]?)", (m) =>
{
string before = m.Groups["Before"].Value;
string after = m.Groups["After"].Value;
string value = m.Groups["Value"].Value;
if (before != "[" || after != "]")
{
return "[A4]";
}
return m.ToString();
});
It is going to replace A and 4 that hasn't been replaced yet for [A4].

Related

How to implement "Find, Replace, Next" in a String on C#?

I'm searching for a solution to this case:
I have a Method inside a DLL that receive a string that contains some words as "placeholders/parameters" that will be replaced by a result of another specific method (inside dll too)
Too simplificate: It's a query string received as an argument to be on a method inside a DLL, where X word that matchs a specifc case, will be replaced.
My method receive a string that could be like this:
(on .exe app)
string str = "INSERT INTO mydb.mytable (id_field, description, complex_number) VALUES ('#GEN_COMPLEX_ID#','A complex solution', '#GEN_COMPLEX_ID#');"
MyDLLClass.MyMethod(str);
So, the problem is: if i replace the #GEN_COMPLEX_ID# on this string, wanting that a different should be on each match, it not will happen because the replaced executes the function in a single shot (not step by step). So, i wanna help to implement this: a step by step replace of any text (like Find some word, replace, than next ... replace ... next... etc.
Could you help me?
Thanks!
This works pretty well for me:
string yourOriginalString = "ab cd ab cd ab cd";
string pattern = "ab";
string yourNewDescription = "123";
int startingPositionOffset = 0;
int yourOriginalStringLength = yourOriginalString.Length;
MatchCollection match = Regex.Matches(yourOriginalString, pattern, RegexOptions.IgnoreCase | RegexOptions.Multiline);
foreach (Match m in match)
{
yourOriginalString = yourOriginalString.Substring(0, m.Index+startingPositionOffset) + yourNewDescription + yourOriginalString.Substring(m.Index + startingPositionOffset+ m.Length);
startingPositionOffset = yourOriginalString.Length - yourOriginalStringLength;
}
If what you're asking is how to replace each placeholder with a different value, you can do it using the Regex.Replace overload which accepts a MatchEvaluator delegate, and executes it for each match:
// conceptually, something like this (note that it's not checking if there are
// enough values in the replacementValues array)
static string ReplaceMultiple(
string input, string placeholder, IEnumerable<string> replacementValues)
{
var enumerator = replacementValues.GetEnumerator();
return Regex.Replace(input, placeholder,
m => { enumerator.MoveNext(); return enumerator.Current; });
}
This is, of course, presuming that all placeholders look the same.
Pseudo-code
var split = source.Split(placeholder); // create array of items without placeholders
var result = split[0]; // copy first item
for(int i = 1; i < result.Length; i++)
{
bool replace = ... // ask user
result += replace ? replacement : placeholder; // to put replacement or not to put
result += split[i]; // copy next item
}
you should use the split method like this
string [] placeholder = {"#Placeholder#"} ;
string[] request = cd.Split(placeholder, StringSplitOptions.RemoveEmptyEntries);
StringBuilder requetBuilding = new StringBuilder();
requetBuilding.Append(request[0]);
int index = 1;
requetBuilding.Append("Your place holder replacement");
requetBuilding.Append(request[index]);
index++; //next replacement
// requetBuilding.Append("Your next place holder replacement");
// requetBuilding.Append(request[index]);

Insert spaces into string using string.format

I've been using C# String.Format for formatting numbers before like this (in this example I simply want to insert a space):
String.Format("{0:### ###}", 123456);
output:
"123 456"
In this particular case, the number is a string. My first thought was to simply parse it to a number, but it makes no sense in the context, and there must be a prettier way.
Following does not work, as ## looks for numbers
String.Format("{0:### ###}", "123456");
output:
"123456"
What is the string equivalent to # when formatting? The awesomeness of String.Format is still fairly new to me.
You have to parse the string to a number first.
int number = int.Parse("123456");
String.Format("{0:### ###}", number);
of course you could also use string methods but that's not as reliable and less safe:
string strNumber = "123456";
String.Format("{0} {1}", strNumber.Remove(3), strNumber.Substring(3));
As Heinzi pointed out, you can not have format specifier for string arguments.
So, instead of String.Format, you may use following:
string myNum="123456";
myNum=myNum.Insert(3," ");
Not very beautiful, and the extra work might outweigh the gains, but if the input is a string on that format, you could do:
var str = "123456";
var result = String.Format("{0} {1}", str.Substring(0,3), str.Substring(3));
string is not a IFormattable
Console.WriteLine("123456" is IFormattable); // False
Console.WriteLine(21321 is IFormattable); // True
No point to supply a format if the argument is not IFormattable only way is to convert your string to int or long
We're doing string manipulation, so we could always use a regex.
Adapted slightly from here:
class MyClass
{
static void Main(string[] args)
{
string sInput, sRegex;
// The string to search.
sInput = "123456789";
// The regular expression.
sRegex = "[0-9][0-9][0-9]";
Regex r = new Regex(sRegex);
MyClass c = new MyClass();
// Assign the replace method to the MatchEvaluator delegate.
MatchEvaluator myEvaluator = new MatchEvaluator(c.ReplaceNums);
// Replace matched characters using the delegate method.
sInput = r.Replace(sInput, myEvaluator);
// Write out the modified string.
Console.WriteLine(sInput);
}
public string ReplaceNums(Match m)
// Replace each Regex match with match + " "
{
return m.ToString()+" ";
}
}
How's that?
It's been ages since I used C# and I can't test, but this may work as a one-liner which may be "neater" if you only need it once:
sInput = Regex("[0-9][0-9][0-9]").Replace(sInput,MatchEvaluator(Match m => m.ToString()+" "));
There is no way to do what you want unless you parse the string first.
Based on your comments, you only really need a simple formatting so you are better off just implementing a small helper method and thats it. (IMHO it's not really a good idea to parse the string if it isn't logically a number; you can't really be sure that in the future the input string might not be a number at all.
I'd go for something similar to:
public static string Group(this string s, int groupSize = 3, char groupSeparator = ' ')
{
var formattedIdentifierBuilder = new StringBuilder();
for (int i = 0; i < s.Length; i++)
{
if (i != 0 && (s.Length - i) % groupSize == 0)
{
formattedIdentifierBuilder.Append(groupSeparator);
}
formattedIdentifierBuilder.Append(s[i]);
}
return formattedIdentifierBuilder.ToString();
}
EDIT: Generalized to generic grouping size and group separator.
The problem is that # is a Digit placeholder and it is specific to numeric formatting only. Hence, you can't use this on strings.
Either parse the string to a numeric, so the formatting rules apply, or use other methods to split the string in two.
string.Format("{0:### ###}", int.Parse("123456"));

Get the different substrings from one main string

I have the following main string which contains link Name and link URL. The name and url is combined with #;. I want to get the string of each link (name and url i.e. My web#?http://www.google.com), see example below
string teststring = "My web#;http://www.google.com My Web2#;http://www.bing.se Handbooks#;http://www.books.se/";
and I want to get three different strings using any string function:
My web#?http://www.google.com
My Web2#?http://www.bing.se
Handbooks#?http://www.books.de
So this looks like you want to split on the space after a #;, instead of splitting at #; itself. C# provides arbitrary length lookbehinds, which makes that quite easy. In fact, you should probably do the replacement of #; with #? first:
string teststring = "My web#;http://www.google.com My Web2#;http://www.bing.se Handbooks#;http://www.books.se/";
teststring = Regex.Replace(teststring, #"#;", "#?");
string[] substrings = Regex.Split(teststring, #"(?<=#\?\S*)\s+");
That's it:
foreach(var s in substrings)
Console.WriteLine(s);
Output:
My web#?http://www.google.com
My Web2#?http://www.bing.se
Handbooks#?http://www.books.se/
If you are worried that your input might already contain other #? that you don't want to split on, you can of course do the splitting first (using #; in the pattern) and then loop over substrings and do the replacement call inside the loop.
If these are constant strings, you can just use String.Substring. This will require you to count letters, which is a nuisance, in order to provide the right parameters, but it will work.
string string1 = teststring.Substring(0, 26).Replace(";","?");
If they aren't, things get complicated. You could almost do a split with " " as the delimiter, except that your site name has a space. Do any of the substrings in your data have constant features, such as domain endings (i.e. first .com, then .de, etc.) or something like that?
If you have any control on the input format, you may want to change it to be easy to parse, for example by using another separator between items, other than space.
If this format can't be changed, why not just implement the split in code? It's not as short as using a RegEx, but it might be actually easier for a reader to understand since the logic is straight forward.
This will almost definitely will be faster and cheaper in terms of memory usage.
An example for code that solves this would be:
static void Main(string[] args)
{
var testString = "My web#;http://www.google.com My Web2#;http://www.bing.se Handbooks#;http://www.books.se/";
foreach(var x in SplitAndFormatUrls(testString))
{
Console.WriteLine(x);
}
}
private static IEnumerable<string> SplitAndFormatUrls(string input)
{
var length = input.Length;
var last = 0;
var seenSeparator = false;
var previousChar = ' ';
for (var index = 0; index < length; index++)
{
var currentChar = input[index];
if ((currentChar == ' ' || index == length - 1) && seenSeparator)
{
var currentUrl = input.Substring(last, index - last);
yield return currentUrl.Replace("#;", "#?");
last = index + 1;
seenSeparator = false;
previousChar = ' ';
continue;
}
if (currentChar == ';' && previousChar == '#')
{
seenSeparator = true;
}
previousChar = currentChar;
}
}

Regex to remove single-line SQL comments (--)

Question:
Can anybody give me a working regex expression (C#/VB.NET) that can remove single line comments from a SQL statement ?
I mean these comments:
-- This is a comment
not those
/* this is a comment */
because I already can handle the star comments.
I have a made a little parser that removes those comments when they are at the start of the line, but they can also be somewhere after code or worse, in a SQL-string 'hello --Test -- World'
Those comments should also be removed (except those in a SQL string of course - if possible).
Surprisingly I didn't got the regex working. I would have assumed the star comments to be more difficult, but actually, they aren't.
As per request, here my code to remove /**/-style comments
(In order to have it ignore SQL-Style strings, you have to subsitute strings with a uniqueidentifier (i used 4 concated), then apply the comment-removal, then apply string-backsubstitution.
static string RemoveCstyleComments(string strInput)
{
string strPattern = #"/[*][\w\d\s]+[*]/";
//strPattern = #"/\*.*?\*/"; // Doesn't work
//strPattern = "/\\*.*?\\*/"; // Doesn't work
//strPattern = #"/\*([^*]|[\r\n]|(\*+([^*/]|[\r\n])))*\*+/ "; // Doesn't work
//strPattern = #"/\*([^*]|[\r\n]|(\*+([^*/]|[\r\n])))*\*+/ "; // Doesn't work
// http://stackoverflow.com/questions/462843/improving-fixing-a-regex-for-c-style-block-comments
strPattern = #"/\*(?>(?:(?>[^*]+)|\*(?!/))*)\*/"; // Works !
string strOutput = System.Text.RegularExpressions.Regex.Replace(strInput, strPattern, string.Empty, System.Text.RegularExpressions.RegexOptions.Multiline);
Console.WriteLine(strOutput);
return strOutput;
} // End Function RemoveCstyleComments
I will disappoint all of you. This can't be done with regular expressions. Sure, it's easy to find comments not in a string (that even the OP could do), the real deal is comments in a string. There is a little hope of the look arounds, but that's still not enough. By telling that you have a preceding quote in a line won't guarantee anything. The only thing what guarantees you something is the oddity of quotes. Something you can't find with regular expression. So just simply go with non-regular-expression approach.
EDIT:
Here's the c# code:
String sql = "--this is a test\r\nselect stuff where substaff like '--this comment should stay' --this should be removed\r\n";
char[] quotes = { '\'', '"'};
int newCommentLiteral, lastCommentLiteral = 0;
while ((newCommentLiteral = sql.IndexOf("--", lastCommentLiteral)) != -1)
{
int countQuotes = sql.Substring(lastCommentLiteral, newCommentLiteral - lastCommentLiteral).Split(quotes).Length - 1;
if (countQuotes % 2 == 0) //this is a comment, since there's an even number of quotes preceding
{
int eol = sql.IndexOf("\r\n") + 2;
if (eol == -1)
eol = sql.Length; //no more newline, meaning end of the string
sql = sql.Remove(newCommentLiteral, eol - newCommentLiteral);
lastCommentLiteral = newCommentLiteral;
}
else //this is within a string, find string ending and moving to it
{
int singleQuote = sql.IndexOf("'", newCommentLiteral);
if (singleQuote == -1)
singleQuote = sql.Length;
int doubleQuote = sql.IndexOf('"', newCommentLiteral);
if (doubleQuote == -1)
doubleQuote = sql.Length;
lastCommentLiteral = Math.Min(singleQuote, doubleQuote) + 1;
//instead of finding the end of the string you could simply do += 2 but the program will become slightly slower
}
}
Console.WriteLine(sql);
What this does: find every comment literal. For each, check if it's within a comment or not, by counting the number of quotes between the current match and the last one. If this number is even, then it's a comment, thus remove it (find first end of line and remove whats between). If it's odd, this is within a string, find the end of the string and move to it. Rgis snippet is based on a wierd SQL trick: 'this" is a valid string. Even tho the 2 quotes differ. If it's not true for your SQL language, you should try a completely different approach. I'll write a program to that too if that's the case, but this one's faster and more straightforward.
You want something like this for the simple case
-{2,}.*
The -{2,} looks for a dash that happens 2 or more times
The .* gets the rest of the lines up to the newline
*But, for the edge cases, it appears that SinistraD is correct in that you cannot catch everything, however here is an article about how this can be done in C# with a combination of code and regex.
This seems to work well for me so far; it even ignores comments within strings, such as SELECT '--not a comment--' FROM ATable
private static string removeComments(string sql)
{
string pattern = #"(?<=^ ([^'""] |['][^']*['] |[""][^""]*[""])*) (--.*$|/\*(.|\n)*?\*/)";
return Regex.Replace(sql, pattern, "", RegexOptions.IgnorePatternWhitespace | RegexOptions.Multiline);
}
Note: it is designed to eliminate both /**/-style comments as well as -- style. Remove |/\*(.|\n)*?\*/ to get rid of the /**/ checking. Also be sure you are using the RegexOptions.IgnorePatternWhitespace Regex option!!
I wanted to be able to handle double-quotes too, but since T-SQL doesn't support them, you could get rid of |[""][^""]*[""] too.
Adapted from here.
Note (Mar 2015): In the end, I wound up using Antlr, a parser generator, for this project. There may have been some edge cases where the regex didn't work. In the end I was much more confident with the results having used Antlr, and it's worked well.
Using System.Text.RegularExpressions;
public static string RemoveSQLCommentCallback(Match SQLLineMatch)
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
bool open = false; //opening of SQL String found
char prev_ch = ' ';
foreach (char ch in SQLLineMatch.ToString())
{
if (ch == '\'')
{
open = !open;
}
else if ((!open && prev_ch == '-' && ch == '-'))
{
break;
}
sb.Append(ch);
prev_ch = ch;
}
return sb.ToString().Trim('-');
}
The code
public static void Main()
{
string sqlText = "WHERE DEPT_NAME LIKE '--Test--' AND START_DATE < SYSDATE -- Don't go over today";
//for every matching line call callback func
string result = Regex.Replace(sqlText, ".*--.*", RemoveSQLCommentCallback);
}
Let's replace, find all the lines that match dash dash comment and call your parsing function for every match.
As a late solution, the simplest way is to do it using ScriptDom-TSqlParser:
// https://michaeljswart.com/2014/04/removing-comments-from-sql/
// http://web.archive.org/web/*/https://michaeljswart.com/2014/04/removing-comments-from-sql/
public static string StripCommentsFromSQL(string SQL)
{
Microsoft.SqlServer.TransactSql.ScriptDom.TSql150Parser parser =
new Microsoft.SqlServer.TransactSql.ScriptDom.TSql150Parser(true);
System.Collections.Generic.IList<Microsoft.SqlServer.TransactSql.ScriptDom.ParseError> errors;
Microsoft.SqlServer.TransactSql.ScriptDom.TSqlFragment fragments =
parser.Parse(new System.IO.StringReader(SQL), out errors);
// clear comments
string result = string.Join(
string.Empty,
fragments.ScriptTokenStream
.Where(x => x.TokenType != Microsoft.SqlServer.TransactSql.ScriptDom.TSqlTokenType.MultilineComment)
.Where(x => x.TokenType != Microsoft.SqlServer.TransactSql.ScriptDom.TSqlTokenType.SingleLineComment)
.Select(x => x.Text));
return result;
}
or instead of using the Microsoft-Parser, you can use ANTL4 TSqlLexer
or without any parser at all:
private static System.Text.RegularExpressions.Regex everythingExceptNewLines =
new System.Text.RegularExpressions.Regex("[^\r\n]");
// http://drizin.io/Removing-comments-from-SQL-scripts/
// http://web.archive.org/web/*/http://drizin.io/Removing-comments-from-SQL-scripts/
public static string RemoveComments(string input, bool preservePositions, bool removeLiterals = false)
{
//based on http://stackoverflow.com/questions/3524317/regex-to-strip-line-comments-from-c-sharp/3524689#3524689
var lineComments = #"--(.*?)\r?\n";
var lineCommentsOnLastLine = #"--(.*?)$"; // because it's possible that there's no \r\n after the last line comment
// literals ('literals'), bracketedIdentifiers ([object]) and quotedIdentifiers ("object"), they follow the same structure:
// there's the start character, any consecutive pairs of closing characters are considered part of the literal/identifier, and then comes the closing character
var literals = #"('(('')|[^'])*')"; // 'John', 'O''malley''s', etc
var bracketedIdentifiers = #"\[((\]\])|[^\]])* \]"; // [object], [ % object]] ], etc
var quotedIdentifiers = #"(\""((\""\"")|[^""])*\"")"; // "object", "object[]", etc - when QUOTED_IDENTIFIER is set to ON, they are identifiers, else they are literals
//var blockComments = #"/\*(.*?)\*/"; //the original code was for C#, but Microsoft SQL allows a nested block comments // //https://msdn.microsoft.com/en-us/library/ms178623.aspx
//so we should use balancing groups // http://weblogs.asp.net/whaggard/377025
var nestedBlockComments = #"/\*
(?>
/\* (?<LEVEL>) # On opening push level
|
\*/ (?<-LEVEL>) # On closing pop level
|
(?! /\* | \*/ ) . # Match any char unless the opening and closing strings
)+ # /* or */ in the lookahead string
(?(LEVEL)(?!)) # If level exists then fail
\*/";
string noComments = System.Text.RegularExpressions.Regex.Replace(input,
nestedBlockComments + "|" + lineComments + "|" + lineCommentsOnLastLine + "|" + literals + "|" + bracketedIdentifiers + "|" + quotedIdentifiers,
me => {
if (me.Value.StartsWith("/*") && preservePositions)
return everythingExceptNewLines.Replace(me.Value, " "); // preserve positions and keep line-breaks // return new string(' ', me.Value.Length);
else if (me.Value.StartsWith("/*") && !preservePositions)
return "";
else if (me.Value.StartsWith("--") && preservePositions)
return everythingExceptNewLines.Replace(me.Value, " "); // preserve positions and keep line-breaks
else if (me.Value.StartsWith("--") && !preservePositions)
return everythingExceptNewLines.Replace(me.Value, ""); // preserve only line-breaks // Environment.NewLine;
else if (me.Value.StartsWith("[") || me.Value.StartsWith("\""))
return me.Value; // do not remove object identifiers ever
else if (!removeLiterals) // Keep the literal strings
return me.Value;
else if (removeLiterals && preservePositions) // remove literals, but preserving positions and line-breaks
{
var literalWithLineBreaks = everythingExceptNewLines.Replace(me.Value, " ");
return "'" + literalWithLineBreaks.Substring(1, literalWithLineBreaks.Length - 2) + "'";
}
else if (removeLiterals && !preservePositions) // wrap completely all literals
return "''";
else
throw new System.NotImplementedException();
},
System.Text.RegularExpressions.RegexOptions.Singleline | System.Text.RegularExpressions.RegexOptions.IgnorePatternWhitespace);
return noComments;
}
I don't know if C#/VB.net regex is special in some way but traditionally s/--.*// should work.
In PHP, i'm using this code to uncomment SQL (only single line):
$sqlComments = '#(([\'"`]).*?[^\\\]\2)|((?:\#|--).*?$)\s*|(?<=;)\s+#ms';
/* Commented version
$sqlComments = '#
(([\'"`]).*?[^\\\]\2) # $1 : Skip single & double quoted + backticked expressions
|((?:\#|--).*?$) # $3 : Match single line comments
\s* # Trim after comments
|(?<=;)\s+ # Trim after semi-colon
#msx';
*/
$uncommentedSQL = trim( preg_replace( $sqlComments, '$1', $sql ) );
preg_match_all( $sqlComments, $sql, $comments );
$extractedComments = array_filter( $comments[ 3 ] );
var_dump( $uncommentedSQL, $extractedComments );
To remove all comments see Regex to match MySQL comments

Remove characters after specific character in string, then remove substring?

I feel kind of dumb posting this when this seems kind of simple and there are tons of questions on strings/characters/regex, but I couldn't find quite what I needed (except in another language: Remove All Text After Certain Point).
I've got the following code:
[Test]
public void stringManipulation()
{
String filename = "testpage.aspx";
String currentFullUrl = "http://localhost:2000/somefolder/myrep/test.aspx?q=qvalue";
String fullUrlWithoutQueryString = currentFullUrl.Replace("?.*", "");
String urlWithoutPageName = fullUrlWithoutQueryString.Remove(fullUrlWithoutQueryString.Length - filename.Length);
String expected = "http://localhost:2000/somefolder/myrep/";
String actual = urlWithoutPageName;
Assert.AreEqual(expected, actual);
}
I tried the solution in the question above (hoping the syntax would be the same!) but nope. I want to first remove the queryString which could be any variable length, then remove the page name, which again could be any length.
How can I get the remove the query string from the full URL such that this test passes?
For string manipulation, if you just want to kill everything after the ?, you can do this
string input = "http://www.somesite.com/somepage.aspx?whatever";
int index = input.IndexOf("?");
if (index >= 0)
input = input.Substring(0, index);
Edit: If everything after the last slash, do something like
string input = "http://www.somesite.com/somepage.aspx?whatever";
int index = input.LastIndexOf("/");
if (index >= 0)
input = input.Substring(0, index); // or index + 1 to keep slash
Alternately, since you're working with a URL, you can do something with it like this code
System.Uri uri = new Uri("http://www.somesite.com/what/test.aspx?hello=1");
string fixedUri = uri.AbsoluteUri.Replace(uri.Query, string.Empty);
To remove everything before the first /
input = input.Substring(input.IndexOf("/"));
To remove everything after the first /
input = input.Substring(0, input.IndexOf("/") + 1);
To remove everything before the last /
input = input.Substring(input.LastIndexOf("/"));
To remove everything after the last /
input = input.Substring(0, input.LastIndexOf("/") + 1);
An even more simpler solution for removing characters after a specified char is to use the String.Remove() method as follows:
To remove everything after the first /
input = input.Remove(input.IndexOf("/") + 1);
To remove everything after the last /
input = input.Remove(input.LastIndexOf("/") + 1);
Here's another simple solution. The following code will return everything before the '|' character:
if (path.Contains('|'))
path = path.Split('|')[0];
In fact, you could have as many separators as you want, but assuming you only have one separation character, here is how you would get everything after the '|':
if (path.Contains('|'))
path = path.Split('|')[1];
(All I changed in the second piece of code was the index of the array.)
The Uri class is generally your best bet for manipulating Urls.
To remove everything before a specific char, use below.
string1 = string1.Substring(string1.IndexOf('$') + 1);
What this does is, takes everything before the $ char and removes it. Now if you want to remove the items after a character, just change the +1 to a -1 and you are set!
But for a URL, I would use the built in .NET class to take of that.
Request.QueryString helps you to get the parameters and values included within the URL
example
string http = "http://dave.com/customers.aspx?customername=dave"
string customername = Request.QueryString["customername"].ToString();
so the customername variable should be equal to dave
regards
I second Hightechrider: there is a specialized Url class already built for you.
I must also point out, however, that the PHP's replaceAll uses regular expressions for search pattern, which you can do in .NET as well - look at the RegEx class.
you can use .NET's built in method to remove the QueryString.
i.e., Request.QueryString.Remove["whatever"];
here whatever in the [ ] is name of the querystring which you want to
remove.
Try this...
I hope this will help.
You can use this extension method to remove query parameters (everything after the ?) in a string
public static string RemoveQueryParameters(this string str)
{
int index = str.IndexOf("?");
return index >= 0 ? str.Substring(0, index) : str;
}

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