How to delete last character in a string in C#?

Question

Building a string for post request in the following way,

  var itemsToAdd = sl.SelProds.ToList();
  if (sl.SelProds.Count() != 0)
  {
      foreach (var item in itemsToAdd)
      {
        paramstr = paramstr + string.Format("productID={0}&", item.prodID.ToString());
      }
  }

after I get resulting paramstr, I need to delete last character & in it

How to delete last character in a string using C#?

Guess it's better to just not add it in the first place, but otherwise you can try paramstr.Substring(0, paramstr.Length - 1) — Jaco Pretorius
– Jaco Pretorius, Commented Sep 19, 2010 at 15:29
In case your prodID is allowed to contain arbitrary characters, especially &, you need to make sure it gets properly escaped, like e.g. the answer of @MarcGravell does. — Evgeniy Berezovsky
– Evgeniy Berezovsky, Commented Aug 14, 2015 at 3:04

Brian Rasmussen · Accepted Answer · 2014-06-20 15:31:32Z

241

Personally I would go with Rob's suggestion, but if you want to remove one (or more) specific trailing character(s) you can use TrimEnd. E.g.

paramstr = paramstr.TrimEnd('&');

edited Jun 20, 2014 at 15:31

answered Sep 19, 2010 at 13:56

Brian Rasmussen

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5 Comments

Doug S Over a year ago

Be aware that TrimEnd will remove all trailing occurrences of that character '&'... so if the string ends with '&&&' then TrimEnd will remove all 3 of those '&', not just the last one. That may or may not be what the OP wants.

Brian Rasmussen Over a year ago

@DougS FWIW I did writer "remove one (or more)".

Joeppie Over a year ago

+1 for a simple solution, that can thus be easily used as a component for other problems. I was searching for a solution to creating a path from multiple parts ensuring I did not have double or missing slashes. Combining TrimEnd and TrimStart with this technique ensures this.

Nigel Touch Over a year ago

@Joeppie: suggest using Path.Combine, which understands all path separators. Leastways use Trim which does start and end in one go.

Joeppie Over a year ago

@Nigel the trouble I have with Path.Combine is that if the second argument starts with a slash, it is interpreted as an absolute path, and the result is the absolute path; this is something I prefer to 'save' people calling my code from. Good point on the Trim, though :)

Rob Fonseca-Ensor · Accepted Answer · 2010-09-19 13:58:51Z

76

build it with string.Join instead:

var parameters = sl.SelProds.Select(x=>"productID="+x.prodID).ToArray();
paramstr = string.Join("&", parameters);

string.Join takes a seperator ("&") and and array of strings (parameters), and inserts the seperator between each element of the array.

answered Sep 19, 2010 at 13:58

Rob Fonseca-Ensor

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4 Comments

Ammar Over a year ago

Worth noting that this is helpful if you don't want to have an & sign at the end of the string.

Jack Marchetti Over a year ago

I knew this was in Ruby, had no idea it was in C# and I'm a .net dev. I feel so embarrassed lol

FastTrack Over a year ago

I can't believe this was the chosen answer... the one just below this by @BrianRasmussen is so much simpler.

Graham Over a year ago

@FastTrack It solved the root problem, versus answering the question in the title. My complaint: if you are going to be fluent, why not just do it all in one line.

Steve Townsend · Accepted Answer · 2010-09-19 13:36:47Z

22

string source;
// source gets initialized
string dest;
if (source.Length > 0)
{
    dest = source.Substring(0, source.Length - 1);
}

answered Sep 19, 2010 at 13:36

Steve Townsend

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Comments

Elmo · Accepted Answer · 2012-01-20 19:14:44Z

15

Try this:

paramstr.Remove((paramstr.Length-1),1);

edited Jan 20, 2012 at 19:14

Elmo

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answered Jan 20, 2012 at 3:21

Nelson T Joseph

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2 Comments

Andrew Barber Over a year ago

Would you consider explaining your answer a little bit, so that others who come along have a better idea why you suggested it?

DavidRR Over a year ago

The answer by @Altaf Patel uses the sibling method String.Remove Method (Int32) which is arguably more straightforward in this situation. However, its good to know about String.Remove Method (Int32, Int32) which offers the ability to trim a substring of arbitrary length from anywhere within the source string.

Matti Virkkunen · Accepted Answer · 2010-09-19 13:43:29Z

13

I would just not add it in the first place:

 var sb = new StringBuilder();

 bool first = true;
 foreach (var foo in items) {
    if (first)
        first = false;
    else
        sb.Append('&');

    // for example:
    var escapedValue = System.Web.HttpUtility.UrlEncode(foo);

    sb.Append(key).Append('=').Append(escapedValue);
 }

 var s = sb.ToString();

edited Sep 19, 2010 at 13:43

Matti Virkkunen

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answered Sep 19, 2010 at 13:36

Marc Gravell

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4 Comments

Matti Virkkunen Over a year ago

I won't say anything about the readability of this snippet, but this is the way I'd do it.

Matt Greer Over a year ago

It's also cheap and easy to just shorten the StringBuilder's length by one after the loop is done.

Guffa Over a year ago

+1 for not adding it instead of removing it, for using a StringBuilder instead of +=, and for chaining appends instead of concatenating and appending. :)

magallanes Over a year ago

The problem with this solution is that the "if" operator is called "n" times.

Altaf Patel · Accepted Answer · 2013-03-04 12:06:31Z

11

string str="This is test string.";
str=str.Remove(str.Length-1);

answered Mar 4, 2013 at 12:06

Altaf Patel

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1 Comment

DavidRR Over a year ago

From String.Remove Method (Int32): "Returns a new string in which all the characters in the current instance, beginning at a specified position and continuing through the last position, have been deleted."

Cheng Chen · Accepted Answer · 2010-09-19 14:02:10Z

7

It's better if you use string.Join.

 class Product
 {
   public int ProductID { get; set; }
 }
 static void Main(string[] args)
 {
   List<Product> products = new List<Product>()
      {   
         new Product { ProductID = 1 },
         new Product { ProductID = 2 },
         new Product { ProductID = 3 }
      };
   string theURL = string.Join("&", products.Select(p => string.Format("productID={0}", p.ProductID)));
   Console.WriteLine(theURL);
 }

answered Sep 19, 2010 at 14:02

Cheng Chen

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3 Comments

One-One Over a year ago

You are missing .ToArray() in your Join statement. +1 though. Helped me.

Cheng Chen Over a year ago

@desaivv: No, I was using this overload: public static string Join<T>(string separator, IEnumerable<T> values), it's new in C# 4.0 :)

One-One Over a year ago

Ahh my bad. Still using VS2008 with 3.0

Dan Diplo · Accepted Answer · 2010-09-19 13:56:32Z

5

It's good practice to use a StringBuilder when concatenating a lot of strings and you can then use the Remove method to get rid of the final character.

StringBuilder paramBuilder = new StringBuilder();

foreach (var item in itemsToAdd)
{
    paramBuilder.AppendFormat(("productID={0}&", item.prodID.ToString());
}

if (paramBuilder.Length > 1)
    paramBuilder.Remove(paramBuilder.Length-1, 1);

string s = paramBuilder.ToString();

answered Sep 19, 2010 at 13:56

Dan Diplo

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1 Comment

Dan Diplo Over a year ago

I also remembered you can use paramBuilder.Length - 1 to remove the last character, too.

DavidRR · Accepted Answer · 2014-06-20 13:30:03Z

1

paramstr.Remove((paramstr.Length-1),1);

This does work to remove a single character from the end of a string. But if I use it to remove, say, 4 characters, this doesn't work:

paramstr.Remove((paramstr.Length-4),1);

As an alternative, I have used this approach instead:

DateFrom = DateFrom.Substring(0, DateFrom.Length-4);

edited Jun 20, 2014 at 13:30

DavidRR

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answered Dec 30, 2013 at 15:29

Uzair Zaman Sheikh

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1 Comment

DavidRR Over a year ago

Using String.Remove Method (Int32, Int32), to remove 4 characters from the end of a string: result = source.Remove((source.Length - 4), 4);.

Md Nazmoon Noor · Accepted Answer · 2014-06-08 22:25:56Z

0

Add a StringBuilder extension method.

public static StringBuilder RemoveLast(this StringBuilder sb, string value)
{
    if(sb.Length < 1) return sb;
    sb.Remove(sb.ToString().LastIndexOf(value), value.Length);
    return sb;
}

then use:

yourStringBuilder.RemoveLast(",");

answered Jun 8, 2014 at 22:25

Md Nazmoon Noor

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