How to determine if string contains specific substring within the first X characters

Admin 1
Viewed 190776

I want to check whether Value1 below contains "abc" within the first X characters. How would you check this with an if statement?

var Value1 = "ddabcgghh";

if (Value1.Contains("abc"))
{
    found = true;
}

It could be within the first 3, 4 or 5 characters.

c#
10 Answers

Or if you need to set the value of found:

found = Value1.StartsWith("abc")

Edit: Given your edit, I would do something like:

found = Value1.Substring(0, 5).Contains("abc")
user_251110

I would use one of the of the overloads of the IndexOf method

bool found = Value1.IndexOf("abc", 0, 7) != -1;
user_1930200

shorter version:

found = Value1.StartsWith("abc");

sorry, but I am a stickler for 'less' code.

Given the edit of the questioner I would actually go with something that accepted an offset, this may in fact be a Great place to an Extension method that overloads StartsWith

public static class StackOverflowExtensions
{
    public static bool StartsWith(this String val, string findString, int count)
    {
        return val.Substring(0, count).Contains(findString);
    }
}
user_407140 
if (Value1.StartsWith("abc")) { found = true; }
olle_483830

Use IndexOf is easier and high performance.

int index = Value1.IndexOf("abc");
bool found = index >= 0 && index < x;
chaowman_23981100

This is what you need : 

if (Value1.StartsWith("abc"))
{
found = true;
}
ScarletGarden_553510

You're close... but use: if (Value1.StartsWith("abc"))

Admin1

A more explicit version is

found = Value1.StartsWith("abc", StringComparison.Ordinal);

It's best to always explicitly list the particular comparison you are doing. The String class can be somewhat inconsistent with the type of comparisons that are used.

JaredPar_232830

You can also use regular expressions (less readable though)

string regex = "^.{0,7}abc";

System.Text.RegularExpressions.Regex reg = new System.Text.RegularExpressions.Regex(regex);
string Value1 = "sssddabcgghh";

Console.WriteLine(reg.Match(Value1).Success);
user_307290
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