how to `.Take()` on a string and get a string at the end?
LINQ to Objects supports queries on string objects but when I use code such as below:
string SomeText = "this is some text in a string";
return SomeText.Take(6).ToString();
All I get is:
System.Linq.Enumerable+<TakeIterator>d__3a`1[System.Ch开发者_JAVA技巧ar]
This is discussed as an "accident" in this question but this is what I am actually trying to do and I cannot find it through search anywhere.
I know there are other ways to manipulate strings but then I also know you can do some really cool tricks with LINQ and I just would like to know if there is a way to trim a string to a certain length with LINQ?
There's no method built in to System.Linq to do this, but you could write your own extension method fairly easily:
public static class StringExtensions
{
public static string ToSystemString(this IEnumerable<char> source)
{
return new string(source.ToArray());
}
}
Unfortunately, because object.ToString
exists on all .NET objects, you would have to give the method a different name so that the compiler will invoke your extension method, not the built-in ToString
.
As per your comment below, it's good to question whether this is the right approach. Because String
exposes a lot of functionality through its public methods, I would implement this method as an extension on String
itself:
/// <summary>
/// Truncates a string to a maximum length.
/// </summary>
/// <param name="value">The string to truncate.</param>
/// <param name="length">The maximum length of the returned string.</param>
/// <returns>The input string, truncated to <paramref name="length"/> characters.</returns>
public static string Truncate(this string value, int length)
{
if (value == null)
throw new ArgumentNullException("value");
return value.Length <= length ? value : value.Substring(0, length);
}
You would use it as follows:
string SomeText = "this is some text in a string";
return SomeText.Truncate(6);
This has the advantage of not creating any temporary arrays/objects when the string is already shorter than the desired length.
Just create string
string res = new string(SomeText.Take(6).ToArray());
Also pay attention to string native methods
string res = SomeText.Substring(0, 6);
I've run into this myself a few times and use the following:
string.Join(string.Empty,yourString.Take(5));
SomeText.Take(6)
will returns an IEnumerable
of char of char, and ToString
method will not return the suspected string you need to call it like the following:
string [] array = SomeText.Take(6).ToArray();
string result = new string(array);
I found this question when I was looking up about LINQ and string.
You can use IEnumerable<char>
instead of string
in returning data type.
You can also learn more about it at How to query for characters in a string (LINQ) (C#)
And here is the solution.
public class Program
{
public static void Main()
{
foreach (var c in LinqString())
{
Console.WriteLine(c);
}
//OR
Console.WriteLine(LinqString().ToArray());
}
private static IEnumerable<char> LinqString()
{
//This is Okay too...
//IEnumerable<char> SomeText = "this is some text in a string";
string SomeText = "this is some text in a string";
return SomeText.Skip(4).Take(6);
}
}
with C# 8 and later...
grab the last 6 digits (fails if the input is less than 8 chars)
string SomeText = "this is some text in a string";
string result = SomeText[^6..];
a protected version that will handle strings less then 6 chars...
string SomeText = "this is some text in a string";
string result = SomeText[^(Math.Min(6, SomeText.Length))..];
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