I want to create a data file, but before writing to the final file I want to drop it in a temporary location to avoid user confussion. As an example, I could begin with test.txt and want to have test.txt.tmp. The names could include a path, but the files may not necesarily exist (so this question is purely about string manipulation).
The closest I have been is to use Path.ChangeExtension:
string original = "test.txt";
string temp = Path.ChangeExtension(original, "tmp");
But that returns test.tmp instead. So my question is if there is a built-in method to achieve that "dual-extension" file name? I could always use brain-dead string concatenation, but I'm looking for a more safe and tested method.
Avoiding pitfalls is a great idea for things like Path.Combine, e.g. because you don't want to be bothered checking if there is no missing \ character.
But there are no pitfalls here.
If your original filename is as you expect it to be, then string concatenation will work.
If your original file name is not as you expect it to be, then the issue lies with whoever supplied you a faulty filename. "Shit goes in, shit comes out" is not really something your internal logic should worry about. An algorithm can only be as correct as the information that it receives.
String concatenation is perfectly acceptable here. There is no premade method here because there is no real pitfall to simply concatenating the strings.
Special shout out to AlessandroD'Andria's suggestion:
Path.ChangeExtension(original, Path.GetExtension(original) + ".tmp");
Technically, it employs Path logic and therefore fits with your criteria. I genuinely like the cleverness of following your expectations.
However, there is simply no merit to doing so. By its very nature an extension is defined as being "the last part of the filename".
Whether you do a direct string concatenation, or instead do this:
chop the string into two pieces (filename, extension)
append something to the last piece (extension + temp extension)
paste everything together again
The end result will always be the same. The chopping of the string is unnecessary work.
Why can't you append that string just like
if(!string.IsNullOrEmpty(Path.GetExtension(original)){
original+= ".tmp";
}
You should use temp file and rename the extension.
string path = Path.GetTempFileName();
// some logic on the file then rename the file and move it when you need it
string fileName = Path.GetFileName(path);
File.Move(path, path.Replace(fileName, "test.txt"));
If you would use temp file, you can use Path.GetTempFileName();
string tempFileName = Path.GetTempFileName();
Or in your case:
string original = "test.txt";
string temp = "test.txt" + ".tmp";
Related
I am developing a program that functions similar to the MS-DOS command "cd". The user types "cd.." into the program's prompt and then, using Stringbuilder, remove the characters representing the user's current directory. It would function like this:
Prompt> cd..
with a Stringbuilder instance declared in the code file:
Stringbuilder builder = new Stringbuilder(#"E:\Folder");
After the user types "cd.." and hits Enter, the program would remove the directory at the end of the Stringbuilder value, with the end result like this:
Stringbuilder builder = new Stringbuilder(#"E:\");
I am not sure how I can do this, or if it is even possible to do. I thought I could try builder.Length - Directory.Length to get the length of the directory name, and then use builder.Remove(int StartIndex, int length), but I don't know how that could be implemented.
Another thing I could possibly use is using builder.ToString() and split it, using the backslash as the seperator.
Any suggestions?
You could use Path.GetDirectoryName, but it's kind of dumb. It just does string manipulation with no idea what the file system actually looks like. For example, if you do Path.GetDirectoryName(#"E:\Folder\") it will return "E:\Folder", because there was a slash at the end of the string you gave it. Or you could feed it a folder that doesn't even exist, and it'll still give you an answer.
I can suggest another way to do this: keep a DirectoryInfo object for the current working directory. For example:
var curDirectory = new DirectoryInfo(#"E:\Folder");
When you need to display it, use curDirecotry.FullName, which will return the full path, like "E:\Folder". Then when you need to go up a directory, it's one line with no string manipulation:
curDirectory = curDirectory.Parent;
Although you do have to check it for null since, if you are already at the root of the drive, Parent will be null.
DirectoryInfo actually looks at the file system so you can be sure that it's always valid. Plus, you can use it for seeing the contents of the folder too, which I'm sure you will want to do.
I use this code for finding the debug directory
public string str_directory = Environment.CurrentDirectory.ToString();
"C:\\Users\\Masoud\\Documents\\Visual Studio 2008\\Projects\\MyProj\\MyProj\\bin\\Debug"
How can I find the parent folder as shown below?
"C:\\Users\\Masoud\\Documents\\Visual Studio 2008\\Projects\\MyProj\\MyProj"
You can use System.IO.Directory.GetParent() to retrieve the parent directory of a given directory.
string parent = System.IO.Directory.GetParent(str_directory).FullName;
See BOL
If you append ..\.. to your existing path, the operating system will correctly browse the grand-parent folder.
That should do the job:
System.IO.Path.Combine("C:\\Users\\Masoud\\Documents\\Visual Studio 2008\\Projects\\MyProj\\MyProj\\bin\\Debug", #"..\..");
If you browse that path, you will browse the grand-parent directory.
Edit: The normalization covered in this answer only happens when the path is used to access the file system, but not on the string itself. By contrast, this answer achieves the result and normalization purely using path strings, without using the file system at all.
I've found variants of System.IO.Path.Combine(myPath, "..") to be the easiest and most reliable. Even more so if what northben says is true, that GetParent requires an extra call if there is a trailing slash. That, to me, is unreliable.
Path.Combine makes sure you never go wrong with slashes.
.. behaves exactly like it does everywhere else in Windows. You can add any number of \.. to a path in cmd or explorer and it will behave exactly as I describe below.
Some basic .. behavior:
If there is a file name, .. will chop that off:
Path.Combine(#"D:\Grandparent\Parent\Child.txt", "..") => D:\Grandparent\Parent\
If the path is a directory, .. will move up a level:
Path.Combine(#"D:\Grandparent\Parent\", "..") => D:\Grandparent\
..\.. follows the same rules, twice in a row:
Path.Combine(#"D:\Grandparent\Parent\Child.txt", #"..\..") => D:\Grandparent\
Path.Combine(#"D:\Grandparent\Parent\", #"..\..") => D:\
And this has the exact same effect:
Path.Combine(#"D:\Grandparent\Parent\Child.txt", "..", "..") => D:\Grandparent\
Path.Combine(#"D:\Grandparent\Parent\", "..", "..") => D:\
To get a 'grandparent' directory, call Directory.GetParent() twice:
var gparent = Directory.GetParent(Directory.GetParent(str_directory).ToString());
Directory.GetParent is probably a better answer, but for completeness there's a different method that takes string and returns string: Path.GetDirectoryName.
string parent = System.IO.Path.GetDirectoryName(str_directory);
Like this:
System.IO.DirectoryInfo myDirectory = new DirectoryInfo(Environment.CurrentDirectory);
string parentDirectory = myDirectory.Parent.FullName;
Good luck!
No one has provided a solution that would work cross-form. I know it wasn't specifically asked but I am working in a linux environment where most of the solutions (as at the time I post this) would provide an error.
Hardcoding path separators (as well as other things) will give an error in anything but Windows systems.
In my original solution I used:
char filesep = Path.DirectorySeparatorChar;
string datapath = $"..{filesep}..{filesep}";
However after seeing some of the answers here I adjusted it to be:
string datapath = Directory.GetParent(Directory.GetParent(Directory.GetCurrentDirectory()).FullName).FullName;
You might want to look into the DirectoryInfo.Parent property.
IO.Path.GetFullPath(#"..\..")
If you clear the "bin\Debug\" in the Project properties -> Build -> Output path, then you can just use AppDomain.CurrentDomain.BaseDirectory
Since nothing else I have found helps to solve this in a truly normalized way, here is another answer.
Note that some answers to similar questions try to use the Uri type, but that struggles with trailing slashes vs. no trailing slashes too.
My other answer on this page works for operations that put the file system to work, but if we want to have the resolved path right now (such as for comparison reasons), without going through the file system, C:/Temp/.. and C:/ would be considered different. Without going through the file system, navigating in that manner does not provide us with a normalized, properly comparable path.
What can we do?
We will build on the following discovery:
Path.GetDirectoryName(path + "/") ?? "" will reliably give us a directory path without a trailing slash.
Adding a slash (as string, not as char) will treat a null path the same as it treats "".
GetDirectoryName will refrain from discarding the last path component thanks to the added slash.
GetDirectoryName will normalize slashes and navigational dots.
This includes the removal of any trailing slashes.
This includes collapsing .. by navigating up.
GetDirectoryName will return null for an empty path, which we coalesce to "".
How do we use this?
First, normalize the input path:
dirPath = Path.GetDirectoryName(dirPath + "/") ?? ""; // To handle nulls, we append "/" rather than '/'
Then, we can get the parent directory, and we can repeat this operation any number of times to navigate further up:
// This is reliable if path results from this or the previous operation
path = Path.GetDirectoryName(path);
Note that we have never touched the file system. No part of the path needs to exist, as it would if we had used DirectoryInfo.
To avoid issues with trailing \, call it this way:
string ParentFolder = Directory.GetParent( folder.Trim('\\')).FullName;
To get your solution
try this
string directory = System.IO.Directory.GetParent(System.IO.Directory.GetParent(Environment.CurrentDirectory).ToString()).ToString();
This is the most common way -- it really depends on what you are doing exactly:
(To explain, the example below will remove the last 10 characters which is what you asked for, however if there are some business rules that are driving your need to find a specific location you should use those to retrieve the directory location, not find the location of something else and modify it.)
// remove last 10 characters from a string
str_directory = str_directory.Substring(0,str_directory.Length-10);
You shouldn't try to do that. Environment.CurrentDirectory gives you the path of the executable directory. This is consistent regardless of where the .exe file is. You shouldn't try to access a file that is assumed to be in a backwards relative location
I would suggest you move whatever resource you want to access into a local location. Of a system directory (such as AppData)
In my case I am using .NET 6. When I use:
public string str_directory = Environment.CurrentDirectory.ToString();
returns C:\Projects\MyTestProject\bin\Debug\net6.0
In order to reach C:\Projects\MyTestProject I am using the following:
Directory.GetParent(Directory.GetCurrentDirectory()).Parent.Parent
You can chain Parent to Directory.GetParent(Environment.CurrentDirectory) in order to reach the directory you want.
Final version:
public string str_directory = Directory.GetParent(Environment.CurrentDirectory).Parent.Parent.ToString();
What I mean by this question is, when you need to store or pass a URL around, using a string is probably a bad practice, and a better approach would be to use a URI type. However it is so easy to make complex things more complex and bloated.
So if I am going to be writing to a file on disk, do I pass it a string, as the file name and file path, or is there a better type that will be better suited to the requirement?
This code seems to be clunky, and error prone? I would also need to do a whole bit of checking if it is a valid file name, if the string contains data and the list goes on.
private void SaveFile(string fileNameAndPath)
{
//The normal stuff to save the file
}
A string is fine for the filename. The .Net Framework uses strings for filenames, that seems fine.
To validate the filename you could try and use a regular expression or check for invalid characters against System.IO.Path.GetInvalidFileNameChars. However, it is probably easier to handle the exceptional cases of invalid filenames by handling the exception that will occur when you try and create the file - plus you need to do this anyway....
Unfortunate as it is, string is the idiomatic way of doing this in .NET - if you look at things like FileStream constructors etc, they use strings.
You could consider using FileInfo (or DirectoryInfo) but that would be somewhat unusual.
You could use FileInfo (from System.IO) to pass it around, but strings are more or less standard when referring to files.
You could always use Path.GetFileName({yourstring}) to get the filename from the path.
String is fine, but you should put in some effort to ensure that the file is being saved into the directory you expect.
If you're working with a filepath a string is usual.
If you're working with a URL you could consider using the System.Uri class e.g.
Uri myUri = new Uri(myUrl, UriKind.Absolute);
This will allow you to work with properties such as uri.Host, uri.Absolute path etc. It will also give you a string array (Segments) for the separate subfolders in the url.
MSDN info here: System.Uri
So I'm trying to create a path in C#. I use Environment.Machinename and store it a variable serverName. Then I create another string variable and have some other path extension in there. Here is my code so far:
string serverName = Environment.MachineName;
string folderName = "\\AlarmLogger";
No matter what I do I can't seem to obtain only one backslash prior to AlarmLogger. Any ideas how I can specify a path in C#?
Edit: I'm wondering if my code doesn't seem to want to paste correctly. Anyways when i paste it I only see one backslash but my code has two. Because of the escape character sequence. But something like
string test = #"\\" + serverName + folderName
doesn't seem to want to work for me.
Use Path.Combine(serverName, folderName). Path.Combine is always a better solution than concating it on your own.
You cannot use Path.Combine for this as suggested. The reason is that it ignores static variables if the first entry is static, e.g. Environment.MachineName (see MSDN docs for details). If you use Path.Combine(servername, foldername) you will get "\AlarmLogger". Plus, it parses double slashs to single slashes.
That being said, you can do something like the following (among other ways):
string serverName = Environment.MachineName;
string folderName = "\\\\AlarmLogger"; //this gives alarmlogger two leading slashes
string test = #"\\" + serverName + folderName.Substring(1,folderName.Length-1); //this removes one of the two leading slashes
You could use a slew of ways to remove the leading slash besides substring.
It's not clear what you are trying to do or what is going wrong.
If you are having trouble including backslashes in your strings, they need to be escaped with an extra backslash:
string twoBackslashes = "\\\\";
Or you can do it like this:
string twoBackslashes = #"\\";
If you are trying to manipulate paths, look at the System.IO.Path class. In particular, Path.Combine can be useful.
I need some Regular expression experts for an extra hand. :)
I have different paths,different folders,different amount of folders.
My question:How do I get the last thing - the filename?
For example in the path:
C:\a\b\c\d\e\fgh.ddj
How do I get "fgh.ddj" with regular expressions?
You don't need regex's, you can do it just like this, its a system.io helper function:
myfilename = Path.GetFileName(mypath);
You can also use FileInfo. When using FileInfo, it actually doesn't matter if the file is present or not.
var fileInfo = new FileInfo("C:\a\b\c\d\e\fgh.ddj");
var fileName = fileInfo.Name;
//this returns "fgh.ddj"
If the file is present, of course there's lots of info about file size, last accessed, etc.
If you have perl installed, then you can try something like this...
#!/usr/bin/perl
use strict;
my $fullname = 'C:\a\b\c\d\e\fgh.ddj';
my $file = (split /\\/, $fullname)[-1];
print $file;