I have one problem in this code. I want to remove all special characters but the square brackets are not getting removed.
string regExp = "[\\\"]";
string tmp = Regex.Replace(str, regExp," ");
string[] strArray = tmp.Split(',');
obj.amcid = db.Execute("select MAX(amcid)+1 from sca_amcmaster");
foreach (string i in strArray)
{
// int myInts = int.Parse(i);
db.Execute(";EXEC insertitems1 #0,#1", i, obj.invoiceno);
}
Square Brackets are metacharacters in Regular Expressions, which allow us to define list of things. So if you want to match then using Regex you need to change your expression to:
string regExp = "\[\\\"\]";
Therefore, you simply need to include the backslashes before the square brackets to match then too.
If none of them are required in the expression, you can group then using brackets, and the character ? (zero or more matches):
string regExp = "(\[)?(\\)?(\")?(\])?";
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 have a string like "aaa\\\\\\\\test.txt".
How do I replace all the repeating \\ characters by a single \\?
I have tried
pPath = new Regex("\\{2,}").Replace(pPath, Path.DirectorySeparatorChar.ToString());
which matches on http://regexstorm.net/tester but doesn't seem to do the trick in my program.
I'm running this on Windows so the Path.DirectorySeparatorChar is a \\.
Use new Regex(#"\\{2,}") and the rest the same.
You need to actually leave the backslash escaped in your regular expression, so you need to produce a string with two backslashes in it. The two equivalent techniques to produce the correct C# string literal are #"\\{2,}" or "\\\\{2,}"
Both of those string literals are the string \\{2,}, which is the correct regular expression. Your regular expression calls for one backslash character occurring two times, and you have to escape the backslash character. At the risk of being pedantic, if you wanted to replace two a characters, you would use the regular expression a{2,} and if you want to replace to \ characters, you would use the regular expression \\{2,} because \\ is the regular expression that matches a single \. Clear as mud? :)
Not being a demi-god at regex, I would use StringBuilder and do something like this:
string txt = "";
int count = 0;
StringBuilder bldr = new StringBuilder();
foreach(char c in txt)
{
if (c == '\')
{
count++;
if (count < 3)
{
bldr.Append(c);
}
}
else
{
count = 0;
bldr.Append(c);
}
}
string result = bldr.ToString();
This is the input string: 23x^45*y or 2x^2 or y^4*x^3.
I am matching ^[0-9]+ after letter x. In other words I am matching x followed by ^ followed by numbers. Problem is that I don't know that I am matching x, it could be any letter that I stored as variable in my char array.
For example:
foreach (char cEle in myarray) // cEle is letter in char array x, y, z, ...
{
match CEle in regex(input) //PSEUDOCODE
}
I am new to regex and I new that this can be done if I define regex variables, but I don't know how.
You can use the pattern #"[cEle]\^\d+" which you can create dynamically from your character array:
string s = "23x^45*y or 2x^2 or y^4*x^3";
char[] letters = { 'e', 'x', 'L' };
string regex = string.Format(#"[{0}]\^\d+",
Regex.Escape(new string(letters)));
foreach (Match match in Regex.Matches(s, regex))
Console.WriteLine(match);
Result:
x^45
x^2
x^3
A few things to note:
It is necessary to escape the ^ inside the regular expression otherwise it has a special meaning "start of line".
It is a good idea to use Regex.Escape when inserting literal strings from a user into a regular expression, to avoid that any characters they type get misinterpreted as special characters.
This will also match the x from the end of variables with longer names like tax^2. This can be avoided by requiring a word boundary (\b).
If you write x^1 as just x then this regular expression will not match it. This can be fixed by using (\^\d+)?.
The easiest and faster way to implement from my point of view is the following:
Input: This?_isWhat?IWANT
string tokenRef = "?";
Regex pattern = new Regex($#"([^{tokenRef}\/>]+)");
The pattern should remove my tokenRef and storing the following output:
Group1 This
Group2 _isWhat
Group3 IWANT
Try using this pattern for capturing the number but excluding the x^ prefix:
(?<=x\^)[0-9]+
string strInput = "23x^45*y or 2x^2 or y^4*x^3";
foreach (Match match in Regex.Matches(strInput, #"(?<=x\^)[0-9]+"))
Console.WriteLine(match);
This should print :
45
2
3
Do not forget to use the option IgnoreCase for matching, if required.
I'm doing some experiments with regular expressions and I don't know why the regex don't match.
string line is one line from a file. A line which should match is this
["boxusers:settings/user[boxuser11]/name"] = "username",
The number of the boxuser and the value could be different, so I tried to find a regular expression
My code is this:
string user;
string patternUser = "[\"boxusers:settings/user[boxuser\\d{2,}]/name\"] = \"";
if (Regex.Match(line,patternUser).Success)
user = Regex.Replace(Regex.Replace(line, patternUser, String.Empty), ",*", String.Empty);
So I think \d{2,0} should be a number with two digits and the rest is just the same. But the regex just don't match.
What's going wrong?
Square brackets have a special significance in regular expressions. You need to escape them with a backslash.
var line = #"[""boxusers:settings/user[boxuser11]/name""] = ""username"", ";
string patternUser = #"\[""boxusers:settings/user\[boxuser\d{2,}\]/name""\] = """;
Console.WriteLine(Regex.Match(line, patternUser).Success);
If you don't want to use verbatim strings, you'll need to use two backslashes to escape each regex metacharacter (the first to escape the second).
string myNumber = "3.44";
Regex regex1 = new Regex(".");
string[] substrings = regex1.Split(myNumber);
foreach (var substring in substrings)
{
Console.WriteLine("The string is : {0} and the length is {1}",substring, substring.Length);
}
Console.ReadLine();
I tried to split the string by ".", but it the splits return 4 empty string. Why?
. means "any character" in regular expressions. So don't split using a regex - split using String.Split:
string[] substrings = myNumber.Split('.');
If you really want to use a regex, you could use:
Regex regex1 = new Regex(#"\.");
The # makes it a verbatim string literal, to stop you from having to escape the backslash. The backslash within the string itself is an escape for the dot within the regex parser.
the easiest solution would be: string[] val = myNumber.Split('.');
. is a reserved character in regex. if you literally want to match a period, try:
Regex regex1 = new Regex(#"\.");
However, you're better off simply using myNumber.Split(".");
The dot matches a single character, without caring what that character
is. The only exception are newline characters.
Source: http://www.regular-expressions.info/dot.html
Therefore your implying in your code to split the string at each character.
Use this instead.
string substr = num.Split('.');
Keep it simple, use String.Split() method;
string[] substrings = myNumber.Split('.');
It has an other overload which allows specifying split options:
public string[] Split(
char[] separator,
StringSplitOptions options
)
You don't need regex you do that by using Split method of string object
string myNumber = "3.44";
String[] substrings = myNumber.Split(".");
foreach (var substring in substrings)
{
Console.WriteLine("The string is : {0} and the length is {1}",substring, substring.Length);
}
Console.ReadLine();
The period "." is being interpreted as any single character instead of a literal period.
Instead of using regular expressions you could just do:
string[] substrings = myNumber.Split(".");
In Regex patterns, the period character matches any single character. If you want the Regex to match the actual period character, you must escape it in the pattern, like so:
#"\."
Now, this case is somewhat simple for Regex matching; you could instead use String.Split() which will split based on the occurrence of one or more static strings or characters:
string[] substrings = myNumber.Split('.');
try
Regex regex1 = new Regex(#"\.");
EDIT: Er... I guess under a minute after Jon Skeet is not too bad, anyway...
You'll want to place an escape character before the "." - like this "\\."
"." in a regex matches any character, so if you pass 4 characters to a regex with only ".", it will return four empty strings. Check out this page for common operators.
Try
Regex regex1 = new Regex("[.]");