What would be the best way and more idiomatic to break a string into two at the place of the last dot? Basically separating the extension from the rest of a path in a file path or URL. So far what I'm doing is Split(".") and then String.Join(".") of everything but the last part. Sounds like using a bazooka to kill flies.
If you want performance, something like:
string s = "a.b.c.d";
int i = s.LastIndexOf('.');
string lhs = i < 0 ? s : s.Substring(0,i),
rhs = i < 0 ? "" : s.Substring(i+1);
You could use Path.GetFilenameWithoutExtension()
or if that won't work for you:
int idx = filename.LastIndexOf('.');
if (idx >= 0)
filename = filename.Substring(0,idx);
To get the path without the extension, use
System.IO.Path.GetFileNameWithoutExtension(fileName)
and to get the extenstion (including the dot), use
Path.GetExtension(fileName)
EDIT:
Unfortunately GetFileNameWithoutExtension strips off the leading path, so instead you could use:
if (path == null)
{
return null;
}
int length = path.LastIndexOf('.');
if (length == -1)
{
return path;
}
return path.Substring(0, length);
The string method LastIndexOf maybe of some use to you here.
But the Path or FileInfo operators will be better suited for filename based operations.
I think what you're really looking for is Path.GetFileNameWithoutExtension Method (System.IO) but just for the heck of it:
string input = "foo.bar.foobar";
int lastDotPosition = input.LastIndexOf('.');
if (lastDotPosition == -1)
{
Console.WriteLine("No dot found");
}
else if (lastDotPosition == input.Length - 1)
{
Console.WriteLine("Last dot found at the very end");
}
else
{
string firstPart = input.Substring(0, lastDotPosition);
string lastPart = input.Substring(lastDotPosition + 1);
Console.WriteLine(firstPart);
Console.WriteLine(lastPart);
}
Path.GetExtension() should help you.
What about using the LastIndexOf method which returns the last found position of a character. Then you can use Substring to extract what you want.
String.LastIndexOf will return you the position of the dot if it ever exists in the string. You can then String.Substring methods to split the string.
You can use string's method
LastIndexOf and substring to acomplish the task.
Related
I use WinForms c#.I have string value like below,
string Something = "1,5,12,34,";
I need to remove last comma in a string. So How can i delete it ?
Try string.TrimEnd():
Something = Something.TrimEnd(',');
King King's answer is of course correct, and Tim Schmelter's comment is also good suggestion in your case.
But if you really want to remove the last comma in a string, you should find the index of the last comma and remove it like this:
string s = "1,5,12,34,12345";
int index = s.LastIndexOf(',');
Console.WriteLine(s.Remove(index, 1));
Output will be:
1,5,12,3412345
Here is a demonstration.
It is unlikely that you want this way but I want to point it out. And remember, the String.Remove method doesn't remove any characters in the original string, it returns new string.
Try string.Remove();
string str = "1,5,12,34,";
string removecomma = str.Remove(str.Length-1);
MessageBox.Show(removecomma);
The TrimEnd method takes an input character array and not a string.
The code below from Dot Net Perls, shows a more efficient example of how to perform the same functionality as TrimEnd.
static string TrimTrailingChars(string value)
{
int removeLength = 0;
for (int i = value.Length - 1; i >= 0; i--)
{
char let = value[i];
if (let == '?' || let == '!' || let == '.')
{
removeLength++;
}
else
{
break;
}
}
if (removeLength > 0)
{
return value.Substring(0, value.Length - removeLength);
}
return value;
}
Dim psValue As String = "1,5,12,34,123,12"
psValue = psValue.Substring(0, psValue.LastIndexOf(","))
output:
1,5,12,34,123
Try below
Something..TrimEnd(",".ToCharArray());
Or you can convert it into Char Array first by:
string Something = "1,5,12,34,";
char[] SomeGoodThing=Something.ToCharArray[];
Now you have each character indexed:
SomeGoodThing[0] -> '1'
SomeGoodThing[1] -> ','
Play around it
When you have spaces at the end. you can use beliow.
ProcessStr = ProcessStr.Replace(" ", "");
Emails = ProcessStr.TrimEnd(';');
Try this,
string Something1= Something.Substring(0, Something.Length - 1 );
I want to find if a string has "/" in front of it, in my code I get indexof of the string and find out if the character before it has anything, which works but how do I find if it actually is forward slash. here is my code:
string test = "/images/";
if (test.IndexOf(#"images/") - 1 == -1)
{
}
EDIT
Some of my strings may have full url and some may be as above and some may not have / at all hence using index of
Do you mean:
if (test.StartsWith("/"))
? (It's not clear what your sample code is trying to achieve.)
Note that "/" is a forward-slash, not a backslash - and you don't need the verbatim string literal in your case, given that the string doesn't contain any backslashes or line breaks.
EDIT: Your question isn't clear, but I suspect you want something like:
int index = test.IndexOf(targetString);
if (index > 0 && test[index - 1] == '/')
{
// There's a leading forward slash. Deal with it appropriately
}
You can use Method StartsWith():
if(test.StartsWith("/"))
{
}
if (test.StartsWith("images") ||
test.IndexOf("/images") > -1 ||
test.IndexOf("\\images") > -1)
Too many good answers :)
Anyway, I meant to say the following:
string str = "/\images\///";
Match matchfirstFwdSlash = Regex.Match(str, "^[\\/]", RegexOptions.IgnoreCase);
if (matchfirstFwdSlash.Success)
{MessageBox .Show ("Success","Success");}
else
{MessageBox .Show ("Oops","Oops");}
//You can find this way
string test = "/Images/";
string a = test.Split('/')[0];
if (a=="")
{
}
If I have the following string:
/lorem/ipsum/dolor
and I want this to become:
/lorem/ipsum
What is the short-hand way of removing the last forward slash, and all characters following it?
I know how I can do this by spliting the string into a List<> and removing the last item, and then joining, but is there a shorter way of writing this?
My question is not URL specific.
You can use Substring() and LastIndexOf():
str = str.Substring(0, str.LastIndexOf('/'));
EDIT (suggested comment)
To prevent any issues when the string may not contain a /, you could use something like:
int lastSlash = str.LastIndexOf('/');
str = (lastSlash > -1) ? str.Substring(0, lastSlash) : str;
Storing the position in a temp-variable would prevent the need to call .LastIndexOf('/') twice, but it could be dropped in favor of a one-line solution instead.
If there is '/' at the end of the url, remove it.
If not; just return the original one.
var url = this.Request.RequestUri.ToString();
url = url.EndsWith("/") ? url.Substring(0, url.Length - 1) : url;
url += #"/mycontroller";
You can do something like str.Remove(str.LastIndexOf("/")), but there is no built-in method to do what you want.
Edit: you could also use the Uri object to traverse directories, although it does not give exactly what you want:
Uri baseUri = new Uri("http://domain.com/lorem/ipsum/dolor");
Uri myUri = new Uri(baseUri, ".");
// myUri now contains http://domain.com/lorem/ipsum/
One simple way would be
String s = "domain.com/lorem/ipsum/dolor";
s = s.Substring(0, s.LastIndexOf('/'));
Console.WriteLine(s);
Another maybe
String s = "domain.com/lorem/ipsum/dolor";
s = s.TrimEnd('/');
Console.WriteLine(s);
You can use the regex /[^/]*$ and replace with the empty string:
var fixed = new Regex("/[^/]*$").Replace("domain.com/lorem/ipsum/dolor", "")
But it's probably overkill here. #newfurniturey's answer of Substring with LastIndexOf is probably best.
I like to create a String Extension for stuff like this:
/// <summary>
/// Returns with suffix removed, if present
/// </summary>
public static string TrimIfEndsWith(
this string value,
string suffix)
{
return
value.EndsWith(suffix) ?
value.Substring(0, value.Length - suffix.Length) :
value;
}
You can then use like this:
var myString = "/lorem/ipsum/dolor";
myStringClean = myString.TrimIfEndsWith("/dolor");
You now have a re-usable extension across all of your projects that can be used to remove one trailing character or multiple.
using System.IO;
mystring.TrimEnd(Path.AltDirectorySeparatorChar); // To remove "/"
mystring.TrimEnd(Path.DirectorySeparatorChar); // To remove "\"
while (input.Last() == '/' || input.Last() == '\\')
{
input = input.Substring(0, input.Length - 1);
}
Thank you #Curt for your question.
I slightly improved #newfurniturey's code, and here is my version.
if(str.Contains('/')){
str = str.Substring(0, str.LastIndexOf('/'));
}
I'm way late to the party, but if you're using C# 8.0+, another clean approach would be to use the range operator:
if (urlStr.EndsWith("/")) urlStr = urlStr[..^1];
If you're curious as to how this works, take a look at the spec for ranges in C#:
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/ranges
tldr; urlStr[..^1] roughly translates to something along the lines of "Give me a substring comprised of the characters contained within the range of index 0 to whatever index is 1 away from the last index.".
In other words, it's similar to...
urlStr.Substring(0, urlStr.Length-1)
How can I get "MyLibrary.Resources.Images.Properties" and "Condo.gif" from a "MyLibrary.Resources.Images.Properties.Condo.gif" string.
I also need it to be able to handle something like "MyLibrary.Resources.Images.Properties.legend.House.gif" and return "House.gif" and "MyLibrary.Resources.Images.Properties.legend".
IndexOf LastIndexOf wouldn't work because I need the second to last '.' character.
Thanks in advance!
UPDATE
Thanks for the answers so far but I really need it to be able to handle different namespaces. So really what I'm asking is how to I split on the second to last character in a string?
You can use LINQ to do something like this:
string target = "MyLibrary.Resources.Images.Properties.legend.House.gif";
var elements = target.Split('.');
const int NumberOfFileNameElements = 2;
string fileName = string.Join(
".",
elements.Skip(elements.Length - NumberOfFileNameElements));
string path = string.Join(
".",
elements.Take(elements.Length - NumberOfFileNameElements));
This assumes that the file name part only contains a single . character, so to get it you skip the number of remaining elements.
You can either use a Regex or String.Split with '.' as the separator and return the second-to-last + '.' + last pieces.
You can look for IndexOf("MyLibrary.Resources.Images.Properties."), add that to MyLibrary.Resources.Images.Properties.".Length and then .Substring(..) from that position
If you know exactly what you're looking for, and it's trailing, you could use string.endswith. Something like
if("MyLibrary.Resources.Images.Properties.Condo.gif".EndsWith("Condo.gif"))
If that's not the case check out regular expressions. Then you could do something like
if(Regex.IsMatch("Condo.gif"))
Or a more generic way: split the string on '.' then grab the last two items in the array.
string input = "MyLibrary.Resources.Images.Properties.legend.House.gif";
//if string isn't already validated, make sure there are at least two
//periods here or you'll error out later on.
int index = input.LastIndexOf('.', input.LastIndexOf('.') - 1);
string first = input.Substring(0, index);
string second = input.Substring(index + 1);
Try splitting the string into an array, by separating it by each '.' character.
You will then have something like:
{"MyLibrary", "Resources", "Images", "Properties", "legend", "House", "gif"}
You can then take the last two elements.
Just break down and do it in a char loop:
int NthLastIndexOf(string str, char ch, int n)
{
if (n <= 0) throw new ArgumentException();
for (int idx = str.Length - 1; idx >= 0; --idx)
if (str[idx] == ch && --n == 0)
return idx;
return -1;
}
This is less expensive than trying to coax it using string splitting methods and isn't a whole lot of code.
string s = "1.2.3.4.5";
int idx = NthLastIndexOf(s, '.', 3);
string a = s.Substring(0, idx); // "1.2"
string b = s.Substring(idx + 1); // "3.4.5"
I have the following:
string test = "9586-202-10072"
How would I get all characters to the right of the final - so 10072. The number of characters is always different to the right of the last dash.
How can this be done?
You can get the position of the last - with str.LastIndexOf('-'). So the next step is obvious:
var result = str.Substring(str.LastIndexOf('-') + 1);
Correction:
As Brian states below, using this on a string with no dashes will result in the original string being returned.
You could use LINQ, and save yourself the explicit parsing:
string test = "9586-202-10072";
string lastFragment = test.Split('-').Last();
Console.WriteLine(lastFragment);
I can see this post was viewed over 46,000 times. I would bet many of the 46,000 viewers are asking this question simply because they just want the file name... and these answers can be a rabbit hole if you cannot make your substring verbatim using the at sign.
If you simply want to get the file name, then there is a simple answer which should be mentioned here. Even if it's not the precise answer to the question.
result = Path.GetFileName(fileName);
see https://msdn.microsoft.com/en-us/library/system.io.path.getfilename(v=vs.110).aspx
string tail = test.Substring(test.LastIndexOf('-') + 1);
YourString.Substring(YourString.LastIndexOf("-"));
With the latest C# 8 and later you can use Range Indexer as follows:-
string test = "9586-202-10072"
var foo = test?[(test.LastIndexOf('-') + 1)..];
// foo is => 10072
string atest = "9586-202-10072";
int indexOfHyphen = atest.LastIndexOf("-");
if (indexOfHyphen >= 0)
{
string contentAfterLastHyphen = atest.Substring(indexOfHyphen + 1);
Console.WriteLine(contentAfterLastHyphen );
}
See String.lastIndexOf method
I created a string extension for this, hope it helps.
public static string GetStringAfterChar(this string value, char substring)
{
if (!string.IsNullOrWhiteSpace(value))
{
var index = value.LastIndexOf(substring);
return index > 0 ? value.Substring(index + 1) : value;
}
return string.Empty;
}
test.Substring[(test.LastIndexOf('-') + 1)..]
C# 8 (late 2019) introduces range operator and simplifies it a bit further. The two dots here means from the index (inclusive) till the end of string.
test.Substring(test.LastIndexOf("-"))
and... in case you need the left part of a string:
private string AllTheLeftPart(string theString)
{
string rightPart = theString.Substring(theString.LastIndexOf('-') + 1);
string leftPart theString.Replace("-" + rightPart, String.Empty);
return leftPart ;
}