Insert string in string

Question

I'm having troubles insert a substring in a string what I want is to inject "/thumbs" into a stringpath

/media/pictures/image1.jpg

I want to inject /thumbs/ into the last part of the path like this:

/media/pictures/thumbs/image1.jpg

Is it possible with linq?

Why would you use linq and not just the String Insert method? — Chris McCabe
– Chris McCabe, Commented Feb 18, 2013 at 20:39
Why would you use link and not just the nice Path utility class meant to help do stuff exactly like this? string pathWithThumbs = Path.Combine(Path.Combine(Path.GetDirectoryName(path), "thumbs"), Path.GetFileName(path)); — Chris Sinclair
– Chris Sinclair, Commented Feb 18, 2013 at 20:39
simple check for the last / (or first from the end) and then insert /thumbs — exexzian
– exexzian, Commented Feb 18, 2013 at 20:40

DiskJunky · Accepted Answer · 2017-10-16 19:36:27Z

4

For something like path manipulation, it's best to use the System.IO namespace, specifically the Path object. You can do something like;

string path = "/media/pictures/image1.jpg";
string newPath = Path.Combine(Path.GetDirectoryName(path), "thumbs", Path.GetFileName(path)).Replace(@"\", "/");

edited Oct 16, 2017 at 19:36

answered Feb 18, 2013 at 20:43

DiskJunky

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Adam K Dean · Accepted Answer · 2013-02-18 20:39:37Z

3

Try this, you get the index of the last forward slash and insert the additional string at that point.

Unsure as to why the downvote, but I assure it works.

string original = "/media/pictures/image1.jpg";
string insert = "thumbs/";
string combined = original.Insert(original.LastIndexOf("/") + 1, insert);

answered Feb 18, 2013 at 20:39

Adam K Dean

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5 Comments

juharr Over a year ago

I didn't down vote, but I assume it's the "you should use Path methods instead of string methods" argument.

Adam K Dean Over a year ago

Most likely, but seems a little bit out of the way for such a simple operation IMO. string.Insert exists for a reason ;)

juharr Over a year ago

Yeah, and I'm not sure the Path methods would keep the slashes going the correct way / vs \

Adam K Dean Over a year ago

It seems silly to use Path.Combine just to replace the slashes afterwards. string.Insert is easier to read as well, no need to over-code it really.

DiskJunky Over a year ago

@AdamKDean, well not in production code. The Path object is a little more versitile and something like this would possibly be put into a common library. A bit of a stretch perhaps but a job worth doing... :-) That said, I do like your approach - neat and to the point!

Soner Gönül · Accepted Answer · 2013-02-18 20:48:57Z

2

Is it possible with linq?

You don't need to use Linq for this process. You can use String.Insert() method;

Returns a new string in which a specified string is inserted at a specified index position in this instance.

string s = "/media/pictures/image1.jpg";
string result = s.Insert(s.LastIndexOf('/'), "/thumbs");
Console.WriteLine(result);

Output;

/media/pictures/thumbs/image1.jpg

Here is a DEMO.

edited Feb 18, 2013 at 20:48

answered Feb 18, 2013 at 20:42

Soner Gönül

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1 Comment

Adam K Dean Over a year ago

That will give /media/pictures/thumbs//image1.jpg, you need to remove one of the slashes.

Chris Sinclair · Accepted Answer · 2013-02-18 20:45:32Z

1

I would use the Path class, preferably in your own utility method or as an extension method.

string pathWithThumbs = Path.Combine(Path.Combine(Path.GetDirectoryName(path), "thumbs"), Path.GetFileName(path));

Linq seems to be out of place here; you're not really querying collections. Plus, the Path class handles most of the slashes and corner cases for you automatically.

EDIT: As @juharr pointed out, as of 4.0 there's a handy overload making it even simpler:

string pathWithThumbs = Path.Combine(Path.GetDirectoryName(path), "thumbs", Path.GetFileName(path));

EDITx2: Hrrrm, as @DiskJunky points out, this Path usage will actually swap your forward slashes for backslashes, so just throw a Replace("\\", "/") call in there.

edited Feb 18, 2013 at 20:45

answered Feb 18, 2013 at 20:40

Chris Sinclair

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4 Comments

juharr Over a year ago

Path.Combine will now take a param array so you don't need to nest them. I think that was added in .Net 4.0.

Chris Sinclair Over a year ago

@juharr Thanks! It's been a long time since I've had to dive into using Path directly; very nice overload!

DiskJunky Over a year ago

The result of your solution replaces the "/" with "\" - you need to complete it with a Replace() call at the end of the chain

Chris Sinclair Over a year ago

@DiskJunky +1 Thanks for picking up on that.

Magnum · Accepted Answer · 2013-02-18 20:46:50Z

I would use System.IO class called Path.

Here is the long(er) version for demonstration purposes only:

string pathToImage = "/media/pictures/image1.jpg";

string dirName = System.IO.Path.GetDirectoryName(pathToImage);
string fileName = System.IO.Path.GetFileName(pathToImage);
string thumbImage = System.IO.Path.Combine(dirName, "thumb", fileName);

Debug.WriteLine("dirName: " + dirName);
Debug.WriteLine("fileName: " + fileName);
Debug.WriteLine("thumbImage: " + thumbImage);

Here is a one-liner:

Debug.WriteLine("ShortHand: " + Path.Combine(Path.GetDirectoryName(pathToImage), "thumb", Path.GetFileName(pathToImage)));

I get the following output:

dirName: \media\pictures
fileName: image1.jpg
thumbImage: \media\pictures\thumb\image1.jpg

ShortHand: \media\pictures\thumb\image1.jpg

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