How to include ":" in a filepath if Spit(':') is used in C#

Question

I have an application where I have to provide number of parameters in the format Name:Value

I provide the list of parameters through the Command line arguments value under "Debug" section of the project

So, it look something like that: "MyJobName" "0" "@FullFilePath:C:\MyFile.txt" "@FileType:MyFileType" "@FileDate:20200318" "@FileID:MyAppID"

One parameter is FilePath:C:\FileDir\MyFileTxt.txt

So, when the following logic is applied:

for (int i = 2; i <= args.GetLength(0) - 1; i++)
{
    L.Add(args[i].Split(':')[0], args[i].Split(':')[1]);
}

My Parameter looks like that: FilePath:C, ignoring the rest of the path.

The final parameter list that I need to pass to the Stored Procedure should have "Name:Value" format

How can I fix that?

You can pass a max array length to the Split method. In this case you can pass 2. `Split(":", 2)`. — Legacy Code, Jul 23 '20 at 19:02
Is the string before first `:` always `FilePath` or can it be different? — Sach, Jul 23 '20 at 19:05
Honestly.. You should not parse parameters like that. Thats just brittle. Use a command line parameter parser like this one https://github.com/commandlineparser/commandline — Legacy Code, Jul 23 '20 at 19:06
@Sach The OP lists several different options in the question... — Heretic Monkey, Jul 23 '20 at 19:06
Didn't you ask the similar [question](https://stackoverflow.com/questions/63040585/index-was-outside-the-bounds-of-the-array-error-in-c-sharp-console-application) already? — Pavel Anikhouski, Jul 23 '20 at 19:44
@PavelAnikhouski I though that too, but the other question was about the Exception he is getting. Proves the fragileness of his code. — Legacy Code, Jul 23 '20 at 19:46

Legacy Code · Answer 1 · 2020-07-23T19:16:10.000

Split lets you pass the maximum array length. See Split Split(Char[], Int32)

Splits a string into a maximum number of substrings based on the characters in an array. You also specify the maximum number of substrings to return.

Sample:

var keyValue = args[i].Split(new char[]{ ':' }, 2);
L.Add(keyValue[0], keyValue[1]);

This way only the first : is taken. The other : that come after it are ignored and will be part of the second item in the array.

But I honestly advise you to use a proper parameter parser, because your approach is very easy to break and very very fragile. https://github.com/commandlineparser/commandline

score 0 · Answer 2 · answered Jul 23 '20 at 19:34

Have a look at dragonfruit and Systel.CommandLine

Instead of writing your arguments parser yourself.

It’s a way to have type safe arguments in your main method.

Scott Hanselman has a great blog post about it.

The great part being your XML comments are used to generate a help message.

score 0 · Answer 3 · answered Jul 23 '20 at 19:53

The moment you use Split, you exclude the delimiter from being a valid character without having to add the extra overloads to it. So if you absolutely must use a colon as your delimiter, you can either use the Split with overload as suggested above, or write extra code to address it;below is how I would parse it.

Of course, a much easier alternative (if possible) would be to change your delimiter to something you know it would never use, something like a pipe or a tilde or a backtick (|, ~, ). Then Split would work cleanly.

"@FullFilePath:C:\MyFile.txt" "@FileType:MyFileType" "@FileDate:20200318" "@FileID:MyAppID"

If your parameters always have the format @ParameterName:ParameterValue, your best bet is to parse the command line args like so:

var argumentsList = new Dictionary<string,object>();
for (int i=2; i < args.Length; i++) 
{
  int colonIndex = args[i].IndexOf(":");
  string parameterName = args[i].Substring(0, colonIndex - 1);
  string parameterValue = args[i].Substring(colonIndex + 1);
  argumentsList[parameterName] = parameterValue;
}

The scope of your question centers around how to get around the colon, so however you choose to store the parameter values is up to you, I just used the dictionary as an example to help wrap up the code.

score -1 · Answer 4 · answered Jul 23 '20 at 19:08

-1

This will skip FilePath and give you C:\FileDir\MyFileTxt.txt

string.Join(":", args[i].Split(':').Skip(1));

answered Jul 23 '20 at 19:08

Eric Sjöström

115
8

This will not give you the file path. It will give you the `C` from this string `@FullFilePath:C:\MyFile.txt` – Legacy Code Jul 23 '20 at 19:17
What? No it wont. If args[i] = @FullFilePath:C:\MyFile.txt it will give you C:\MyFile.txt. Try it before you down vote – Eric Sjöström Jul 23 '20 at 19:25
It will give you an IEnumeration with 2 elements. Technically not a string. You have to join them `string.Join(":", bla)` to get the required result. – Legacy Code Jul 23 '20 at 19:33
That is exactly what i wrote, but you save args[i].Split(':').Skip(1) in a variable first. But it's exactly the same code – Eric Sjöström Jul 23 '20 at 19:35
Try this Console.Log Genius `Console.WriteLine(string.Join(":", @"FullFilePath:C:\MyFile.txt".Split(':').Skip(1)));` – Eric Sjöström Jul 23 '20 at 19:42
Sorry I might have not seen the `string.Join` in the first place, but the fact that you split the string to then join them is a bit ineffective. It's like using a json deserializer to clone an object. – Legacy Code Jul 23 '20 at 19:43
It's the best one liner I know to solve this problem to do it dynamic. If the text would contain more ":". Something like this "FullFilePath:C:\My:File.txt:test" and you only want to remove the first :. Sure there might exist some more effective way. But this will never affect performance – Eric Sjöström Jul 23 '20 at 19:49
`Split(Char[], Int32)` – Legacy Code Jul 23 '20 at 19:55

How to include ":" in a filepath if Spit(':') is used in C#

4 Answers4