Maybe this is a silly question. But I haven't found an answer yet.
I've got some strings. I would like to concatenate them and then split the resulting string in a different moment. I would like to know if there's something available inside the .NET Framework. The Join and Split methods of String work quite well. The problem is to escape the separator character.
For example, I would like to use the "#" as separator character. If I have "String1", "Str#ing2" and "String3", I would like to obtain "String1#Str##ing2#String3".
Is there something that does what I need or do I have to write my own function?
Thank you.
Just escape the separator on the way in.
var inputs = ["String1", "Str#ing2", "String3"];
var joined = string.Join(inputs.Select(i => i.Replace("#", "##"));
You can then split on single # chars.
var split = Regex.Split(joined, "(?<!#)#(?!#)");
This uses zero-width negative lookbehind/lookahead patterns to assert the character before and after the # is not another #. You should run some tests on cases where # is at the start or end of your input strings however.
Call .Replace("#", "##") on each string before passing them to .Join
Related
I need to compare strings with standard string structure.
string structure = Bank*Loan*1.pdf;
string name = BankAutoLoanByCustomer1.pdf;
How to compare name string with standard string structure? I am trying to get whether skeleton of name is same as of skeleton of structure.
You test it like this:
bool matches = Regex.IsMatch(name, structure);
However, regex syntax is different to what you're using.
A few special characters you need:
. = any single character
* = 0 or more times
\ = escape character: treat the next character literally, not as a special character.
So, your structure should be more like:
string structure = "Bank.*Loan.*1\\.pdf";
Note that you actually have to use two slashes to escape a character, because C# strings also use \ as an escape character.
You can utilize Operators.LikeString method.
bool isMatch = Operators.LikeString("BankAutoLoanByCustomer1.pdf", "Bank*Loan*1.pdf", Microsoft.VisualBasic.CompareMethod.Text);
Based on your loose criteria:
Regex.IsMatch(name, #"^Bank.*Loan.*1\.pdf$");
So you want to match Bank anything Loan anything 1.pdf?
In that case, you can use the Regex
Bank.*Loan.*1\.pdf
The period means "ANY character except newline". The star means "0 or more times". The \ escapes the period before pdf, because we want an actual period, not an "ANY character except newline".
First you should learn how to declare strings in c# - you need to use double quotes ""
string structure = "Bank*Loan*1.pdf";
string name = "BankAutoLoanByCustomer1.pdf";
Secondly you should ask the right questions - as I see you basically want to find files in a directory that match a specific pattern and then you can use
Directory.GetFiles("directoryName", structure)
I need to remove leading zeroes from the numerical part of an expression (using .net 2.0 C# Regex class).
Ex:
PAR0000034 -> PAR34
WP0003204 -> WP3204
I tried the following:
//keep starting characters, get rid of leading zeroes, keep remaining digits
string result = Regex.Replace(inputStr, "^(.+)(0+)(/d*)", "$1$3", RegexOptions.IgnoreCase)
Obviously, it did not work. I need a bit of help to find the mistake.
You don't need a regular expression for that, the Split method can do that for you.
Splitting on '0', removing empty entries (i.e. between the mulitple zeroes), and limiting the result to two strings will give you the two strings before and after the leading zeroes. Then you just put those two strings together again:
string result = String.Concat(
input.Split(new char[] { '0' }, 2, StringSplitOptions.RemoveEmptyEntries)
);
In your expression the .* part is greedy, so it catches full string. Further
use backslash instead of slash for digit \d
string result = Regex.Replace(inputStr, #"^([^0]+)(0+)(\d*)", "$1$3");
Or use look behind instead:
string result = Regex.Replace(inputStr, "(?<=[a-zA-Z])0+", "");
This works for me:
Regex.Replace("PPP00001001", "([^0]*)0+(.*)", "$1$2");
The phrase "leading zeroes" is confusing, since the zeroes you're talking about aren't actually at the beginning of the string. But if I understand you correctly, you want this:
string result = Regex.Replace(inputStr, "^(.*?)0+", "$1");
There are actually several ways to do it, with and without regex, but the above is probably the shortest and easiest to understand. The important part is the .*? lazy quantifier. This will ensure that it a) finds only the first string of zeroes, and b) deletes all the "leading" zeroes in the string.
This has probably been answered somewhere before but since there are millions of unrelated posts about string formatting.
Take the following string:
24:Something(true;false;true)[0,1,0]
I want to be able to do two things in this case. I need to check whether or not all the following conditions are true:
There is only one : Achieved using Split() which I needed to use anyway to separate the two parts.
The integer before the : is a 1-3 digit int Simple int.parse logic
The () exists, and that the "Something", in this case any string less than 10 characters, is there
The [] exists and has at least 1 integer in it. Also, make sure the elements in the [] are integers separated by ,
How can I best do this?
EDIT: I have crossed out what I've achieved so far.
A regular expression is the quickest way. Depending on the complexity it may also be the most computationally expensive.
This seems to do what you need (I'm not that good so there might be better ways to do this):
^\d{1,3}:\w{1,9}\((true|false)(;true|;false)*\)\[\d(,[\d])*\]$
Explanation
\d{1,3}
1 to 3 digits
:
followed by a colon
\w{1,9}
followed by a 1-9 character alpha-numeric string,
\((true|false)(;true|;false)*\)
followed by parenthesis containing "true" or "false" followed by any number of ";true" or ";false",
\[\d(,[\d])*\]
followed by another set of parenthesis containing a digit, followed by any number of comma+digit.
The ^ and $ at the beginning and end of the string indicate the start and end of the string which is important since we're trying to verify the entire string matches the format.
Code Sample
var input = "24:Something(true;false;true)[0,1,0]";
var regex = new System.Text.RegularExpressions.Regex(#"^\d{1,3}:.{1,9}\(.*\)\[\d(,[\d])*\]$");
bool isFormattedCorrectly = regex.IsMatch(input);
Credit # Ian Nelson
This is one of those cases where your only sensible option is to use a Regular Expression.
My hasty attempt is something like:
var input = "24:Something(true;false;true)[0,1,0]";
var regex = new System.Text.RegularExpressions.Regex(#"^\d{1,3}:.{1,9}\(.*\)\[\d(,[\d])*\]$");
System.Diagnostics.Debug.Assert(regex.IsMatch(input));
This online RegEx tester should help refine the expression.
I think, the best way is to use regular expressions like this:
string s = "24:Something(true;false;true)[0,1,0]";
Regex pattern = new Regex(#"^\d{1,3}:[a-zA-z]{1,10}\((true|false)(;true|;false)*\)\[\d(,\d)*\]$");
if (pattern.IsMatch(s))
{
// s is valid
}
If you want anything inside (), you can use following regex:
#"^\d{1,3}:[a-zA-z]{1,10}\([^:\(]*\)\[\d(,\d)*\]$"
I'm currently facing a (little) blocking issue. I'd like to replace a substring by one another using regular expression. But here is the trick : I suck at regex.
Regex.Replace(contenu, "Request.ServerVariables("*"))",
"ServerVariables('test')");
Basically I'd like to replace whatever is between the " by "test". I tried ".{*}" as a pattern but it doesn't work.
Could you give me some tips, I'd appreciate it!
There are several issues you need to take care of.
You are using special characters in your regex (., parens, quotes) -- you need to escape these with a slash. And you need to escape the slashes with another slash as well because we 're in a C# string literal, unless you prefix the string with # in which case the escaping rules are different.
The expression to match "any number of whatever characters" is .*. In this case, you would want to match any number of non-quote characters, which is [^"]*.
In contrast to (1) above, the replacement string is not a regular expression so you don't want any slashes there.
You need to store the return value of the replace somewhere.
The end result is
var result = Regex.Replace(contenu,
#"Request\.ServerVariables\(""[^""]*""\)",
"Request.ServerVariables('test')");
Based purely on my knowledge of regex (and not how they are done in C#), the pattern you want is probably:
"[^"]*"
ie - match a " then match everything that's not a " then match another "
You may need to escape the double-quotes to make your regex-parser actually match on them... that's what I don't know about C#
Try to avoid where you can the '.*' in regex, you can usually find what you want to get by avoiding other characters, for example [^"]+ not quoted, or ([^)]+) not in parenthesis. So you may just want "([^"]+)" which should give you the whole thing in [0], then in [1] you'll find 'test'.
You could also just replace '"' with '' I think.
Taryn Easts regex includes the *. You should remove it, if it is just a placeholder for any value:
"[^"]"
BTW: You can test this regex with this cool editor: http://rubular.com/r/1MMtJNF3kM
I'd thought i do a regex replace
Regex r = new Regex("[0-9]");
return r.Replace(sz, "#");
on a file named aa514a3a.4s5 . It works exactly as i expect. It replaces all the numbers including the numbers in the ext. How do i make it NOT replace the numbers in the ext. I tried numerous regex strings but i am beginning to think that its a all or nothing pattern so i cant do this? do i need to separate the ext from the string or can i use regex?
This one does it for me:
(?<!\.[0-9a-z]*)[0-9]
This does a negative lookbehind (the string must not occur before the matched string) on a period, followed by zero or more alphanumeric characters. This ensures only numbers are matched that are not in your extension.
Obviously, the [0-9a-z] must be replaced by which characters you expect in your extension.
I don't think you can do that with a single regular expression.
Probably best to split the original string into base and extension; do the replace on the base; then join them back up.
Yes, I thing you'd be better off separating the extension.
If you are sure there is always a 3-character extension at the end of your string, the easiest, most readable/maintainable solution would be to only perform the replace on
yourString.Substring(0,YourString.Length-4)
..and then append
yourString.Substring(YourString.Length-4, 4)
Why not run the regex on the substring?
String filename = "aa514a3a.4s5";
String nameonly = filename.Substring(0,filename.Length-4);