Develop Reference

Matching a Pattern in C#

This may seem like an obvious thing, but I want to know know if there are wildcards in C# for matching strings.
I want to write a program so that users can search for something based on the date value in the database. What I have so far works as long as the whole date is entered, but entering half a date causes a parsing error
I'm using this code now
" ... where Date like " DateTime.Parse(textbox.text.trim()) " + %;"
I want to see if there is an way to see what the user input (only the year, or month and year without day, or for it not to crash if only half the year is entered)
A solution that involves doing this in SQL itself doesn't matter

Solution 1:
public static class MyStringExtensions
{
public static bool Like(this string toSearch, string toFind)
{
return new Regex(#"\A" + new Regex(#"\.|\$|\^|\{|\[|\(|\||\)|\*|\+|\?|\\").Replace(toFind, ch => #"\" + ch).Replace('_', '.').Replace("%", ".*") + #"\z", RegexOptions.Singleline).IsMatch(toSearch);
}
}
examples:
bool willBeTrue = "abcdefg".Like("abcd_fg");
bool willAlsoBeTrue = "abcdefg".Like("ab%f%");
bool willBeFalse = "abcdefghi".Like("abcd_fg");
Solution2:
madate.ToString().Contain("myvalue")
madate.ToString().StartWith("myvalue")
madate.ToString().EndWith("myvalue")
or use sql :
where CONVERT(VARCHAR(24),yourdate, 103) like '%yourvalue%'

where CONVERT(VARCHAR(24),yourdate, 103) like '%yourvalue%'

Regex.Match doesnt work correctly

I have a string extension that was defined exactly like this:
public static string GetStringBetween(this string value, string start, string end)
{
start = Regex.Escape(start);
end = Regex.Escape(end);
GroupCollection matches = Regex.Match(value, start + #"([^)]*)" + end).Groups;
return matches[1].Value;
}
But when I call this:
string str = "The pre-inspection image A. Valderama (1).jpg of client Valderama is not...";
Console.WriteLine(str.GetStringBetween("pre-inspection image ", " of client"));
It doesn't write anything. But when the str value is like this:
string str = "The pre-inspection image A. Valderama.jpg of client Valderama is not...";
It works fine. Why was it like this?
My code is in C#, framework 4, build in VS2010 Pro.
Please help. Thanks in advance.

Because you specify to exclude the character ) in the capturing group of your regex: [^)] in #"([^)]*)"
And since ) appears in the first string: Valderama (1).jpg, it will not be able to match.
You probably want #"(.*)" instead.

C# 2.0 function which will return the formatted string

I am using C# 2.0 and I have got below type of strings:
string id = "tcm:481-191820"; or "tcm:481-191820-32"; or "tcm:481-191820-8"; or "tcm:481-191820-128";
The last part of string doesn't matter i.e. (-32,-8,-128), whatever the string is it will render below result.
Now, I need to write one function which will take above string as input. something like below and will output as "tcm:0-481-1"
public static string GetPublicationID(string id)
{
//this function will return as below output
return "tcm:0-481-1"
}
Please suggest!!

If final "-1" is static you could use:
public static string GetPublicationID(string id)
{
int a = 1 + id.IndexOf(':');
string first = id.Substring(0, a);
string second = id.Substring(a, id.IndexOf('-') - a);
return String.Format("{0}0-{1}-1", first, second);
}
or if "-1" is first part of next token, try this
public static string GetPublicationID(string id)
{
int a = 1 + id.IndexOf(':');
string first = id.Substring(0, a);
string second = id.Substring(a, id.IndexOf('-') - a + 2);
return String.Format("{0}0-{1}", first, second);
}
This syntax works even for different length patterns, assuming that your string is
first_part:second_part-anything_else

All you need is:
string.Format("{0}0-{1}", id.Substring(0,4), id.Substring(4,5));
This just uses substring to get the first four characters and then the next five and put them into the format with the 0- in there.
This does assume that your format is a fixed number of characters in each position (which it is in your example). If the string might be abcd:4812... then you will have to modify it slightly to pick up the right length of strings. See Marco's answer for that technique. I'd advise using his if you need the variable length and mine if the lengths stay the same.
Also as an additional note your original function of returning a static string does work for all of those examples you provided. I have assumed there are other numbers visible but if it is only the suffix that changes then you could happily use a static string (at which point declaring a constant or something rather than using a method would probably work better).

Obligatory Regular Expression Answer:
using System.Text.RegularExpressions;
public static string GetPublicationID(string id)
{
Match m = RegEx.Match(#"tcm:([\d]+-[\d]{1})", id);
if(m.Success)
return string.Format("tcm:0-{0}", m.Groups[1].Captures[0].Value.ToString());
else
return string.Empty;
}

Regex regxMatch = new Regex("(?<prefix>tcm:)(?<id>\\d+-\\d)(?<suffix>.)*",RegexOptions.Singleline|RegexOptions.Compiled);
string regxReplace = "${prefix}0-${id}";
string GetPublicationID(string input) {
return regxMatch.Replace(input, regxReplace);
}
string test = "tcm:481-191820-128";
stirng result = GetPublicationID(test);
//result: tcm:0-481-1

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;
}

Convert String to Integer [duplicate]

This question already has answers here:
Closed 13 years ago.
Possible Duplicate:
how can I convert String to Int ?
Hi,
I have the following problem converting string to an integer:
string str = line.Substring(0,1);
//This picks an integer at offset 0 from string 'line'
So now string str contains a single integer in it. I am doing the following:
int i = Convert.ToInt32(str);
i should be printing an integer if I write the following statement right?
Console.WriteLine(i);
It compiles without any error but gives the following error on runtime:
An unhandled exception of type 'System.FormatException' occurred in mscorlib.dll
Additional information: Input string was not in a correct format.
Any help please?

Rather than using Convert.ToInt32(string) you should consider using Int32.TryParse(string, out int) instead. The TryParse methods are there to help deal with user-provided input in a safer manner. The most likely cause of your error is that the substring you are returning has an invalid string representation of an integer value.
string str = line.Substring(0,1);
int i = -1;
if (Int32.TryParse(str, out i))
{
Console.WriteLine(i);
}

FormatException
value does not consist of an optional
sign followed by a sequence of digits
(0 through 9).
The exception that is thrown when the
format of an argument does not meet
the parameter specifications of the
invoked method.
You can use Int32.TryParse if you don't want to generate an exception like this.
Int32.TryParse: Converts the string representation of
a number to its 32-bit signed integer
equivalent. A return value indicates
whether the operation succeeded.

It's entirely possible there is some whitespace in there. Try running something akin to trim() (I'm not sure what language you're in) that will strip the white space. Also, try printing out the string to make sure you actually have the right part of it. We've all done that :)

It's likely that your input is not a valid format. Try this instead. If the number is not valid, it should output an error.
Keep in mind that the string should consist of an optional sign followed by a number.
string line = "23"; // or whatever.
string str = line.Substring(0,1);
int i = 0;
if (Int32.TryParse(str, out i)) {
Console.WriteLine(i);
} else {
Console.WriteLine ("Error converting '" + line + "', '" + str + "'.");
}
One thing you may be seeing is the user entering "-1" for example. If you do the substring(0,1) on that, you'll only get "-" which isn't really valid.

Are you sure that the value returned in str is an int, set a debug point if your using visual studio. Ive got a feeling your problem maybe that your not actually returning an integer. Try:
line.Trim().Substring(0,1);
This will remove any whitespace.