How can I check if a string contains another string in C#

Question

I have strings like this:

var a = "abcdef  * dddddd*jjjjjjjjjjjjj";
var b = "aaaaaaaaaaaaaaaaaaaaaaaa * aaaaaa";
var c = "hhhhhhhhhhhhhhhhhhhhhhhhhhh";

Is there a smile way for me to check if the string contains a " * " within the first 20 characters?

Andreas Eriksson · Accepted Answer · 2011-08-11 11:29:08Z

5

Try this

a.IndexOf('*') >= 0 && a.IndexOf('*') < 20

Should work like a charm

Edit: IndexOf will also return -1 if the char wasn't found at all, which could be useful information i guess.

edited Aug 11, 2011 at 11:29

answered Aug 11, 2011 at 11:23

Andreas Eriksson

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1 Comment

herzmeister Over a year ago

You forgot to also check for > -1

Nick Spiers · Accepted Answer · 2011-08-11 11:23:14Z

3

a.Substring(0, 20).Contains('*');

answered Aug 11, 2011 at 11:23

Nick Spiers

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Stephan Bauer Over a year ago

This will throw an ArgumentOutOfRangeException if the string has a length less than 20.

JohnD · Accepted Answer · 2011-08-11 11:25:54Z

2

This will do it, but you should check the string length -- this code will fail if the string is too short:

bool b1 = a.Substring(0, 20).Contains('*');

answered Aug 11, 2011 at 11:25

JohnD

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Comments

JK. · Accepted Answer · 2011-08-11 11:47:55Z

2

bool contains = (a.Length > 20) ? a.Substring(0, 20).Contains("*") : a.Contains("*");

if(contains)
{
  etc...

edited Aug 11, 2011 at 11:47

answered Aug 11, 2011 at 11:22

JK.

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2 Comments

Stephan Bauer Over a year ago

This will throw an ArgumentOutOfRangeException if the string has a length less than 20.

Jason Over a year ago

@Jk - I tried all the solutions but there is a problem. What if the line is less than 20 characters long?

Ankur · Accepted Answer · 2011-08-11 11:35:29Z

0

Using Linq:

 a.Take(20).Contains('*')

This is the simplest and efficient than sub string based solution as it doesn't create new string object

edited Aug 11, 2011 at 11:35

answered Aug 11, 2011 at 11:24

Ankur

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