Left function in c#

Question

what is the alternative for Left function in c# i have this in

Left(fac.GetCachedValue("Auto Print Clinical Warnings").ToLower + " ", 1) == "y");

This isn't a full question- what is this Left function? Why are you looking for an alternative to it? What is your expected input/output? — Chris Shain, Sep 27 '11 at 19:27
Left in Vb.net..i have to convert this to c#.Now i got the answer tnaks — , Sep 27 '11 at 19:40
This is not a duplicate...the other question asks for a vb 6 function in a vb.net program. This question asks for a C# answer — Ggalla1779, Jan 06 '17 at 09:42
Or: `return value == null ? value : string.Concat(value.Take(maxLength));` — Rufus L, Aug 02 '18 at 23:59

score 135 · Accepted Answer · edited May 07 '15 at 02:37

135

It sounds like you're asking about a function

string Left(string s, int left)

that will return the leftmost left characters of the string s. In that case you can just use String.Substring. You can write this as an extension method:

public static class StringExtensions
{
    public static string Left(this string value, int maxLength)
    {
        if (string.IsNullOrEmpty(value)) return value;
        maxLength = Math.Abs(maxLength);

        return ( value.Length <= maxLength 
               ? value 
               : value.Substring(0, maxLength)
               );
    }
}

and use it like so:

string left = s.Left(number);

For your specific example:

string s = fac.GetCachedValue("Auto Print Clinical Warnings").ToLower() + " ";
string left = s.Substring(0, 1);

edited May 07 '15 at 02:37

Diego

18,035
5
62
66

answered Sep 27 '11 at 19:27

jason

236,483
35
423
525

@Roland Illig: Yes, but as I mentioned, "I'll leave the error handling to you." – jason Sep 27 '11 at 19:46
3

Edited to pass through null, empty and shorter than desired strings unchanged. – Stephen Turner Oct 09 '14 at 10:36
Thank you Clippy – Amicable Dec 17 '18 at 14:36
It's still much more code than the one-liner from my answer. Also, in the "specific example" code you don't use the `Left` function at all. – Roland Illig Sep 06 '19 at 00:13
See Also: Right function https://stackoverflow.com/questions/16782786/right-function-in-c – viggity Sep 22 '21 at 12:37

Peter O. · Answer 2 · 2017-11-01T07:28:27.967

63

It's the Substring method of String, with the first argument set to 0.

 myString.Substring(0,1);

[The following was added by Almo; see Justin J Stark's comment. —Peter O.]

Warning: If the string's length is less than the number of characters you're taking, you'll get an ArgumentOutOfRangeException.

edited Nov 01 '17 at 07:28

answered Sep 27 '11 at 19:29

Peter O.

32,158
14
82
96

13

Careful: If the string's length is less than the number of characters you're taking, you'll get an ArgumentOutOfRangeException. – Justin J Stark Sep 20 '16 at 21:44
9

I use Math.Min to avoid the ArgumentOutOfRangeException: myString.Substring(0, Math.Min(numberOfCharacters, myString.Length)) – Nugsson Sep 04 '18 at 11:02

Roland Illig · Answer 3 · 2016-08-09T20:37:10.957

19

Just write what you really wanted to know:

fac.GetCachedValue("Auto Print Clinical Warnings").ToLower().StartsWith("y")

It's much simpler than anything with substring.

edited Aug 09 '16 at 20:37

answered Sep 27 '11 at 19:30

Roland Illig

40,703
10
88
121

1

You nailed it. Why has this best answer not 1000 points ? – fbehrens Aug 22 '19 at 13:00
Because I came too late to the party. The other answers were already there and had gained enough reputation, even if they didn't answer the _actual_ question, which was an [XY problem](https://en.wikipedia.org/wiki/XY_problem). – Roland Illig Mar 19 '22 at 21:16

score 10 · Answer 4 · answered Sep 27 '11 at 19:28

10

use substring function:

yourString.Substring(0, length);

answered Sep 27 '11 at 19:28

Davide Piras

43,984
10
98
147

9

Careful: If the string's length is less than the number of characters you're taking, you'll get an ArgumentOutOfRangeException. – Justin J Stark Sep 20 '16 at 21:44
1

I use Math.Min to avoid the ArgumentOutOfRangeException: yourString.Substring(0, Math.Min(numberOfCharacters, yourString.Length)) – Nugsson Nov 24 '20 at 13:32

score -1 · Answer 5 · answered Sep 27 '11 at 19:29

-1

var value = fac.GetCachedValue("Auto Print Clinical Warnings")
// 0 = Start at the first character
// 1 = The length of the string to grab
if (value.ToLower().SubString(0, 1) == "y")
{
    // Do your stuff.
}

answered Sep 27 '11 at 19:29

Matt Grande

11,964
6
62
89

This code does not handle the empty string correctly, it throws an ArgumentOutOfRangeException in that case. – Roland Illig Dec 12 '18 at 16:32

Left function in c#

5 Answers5

Linked