Look for part of a string in an array?

Question

i'm looking for an efficient way to look for certain words, would i use switch/case, int/string.IndexOf('!'); foreach loop/contains?

i have a string that i'm receiving from a client. so, let's say i get:

string x = "fjdswordslkjf?dkHEYw";

i have an array of possible values that correspond with that message. (none of this is syntactically correct, just so you get an idea):

someArray[0]= "?";
someArray[1]= "HEY";
someArray[2]= "find.me";

basically i want to know

 if (x contains someWordinSomeArray)

i want to search through the string x, using the words in the array. what would be the most efficient way to do this in c#? i just need a bool response, not the exact location in the string.

ANSWER

here's what i used:

foreach (string searchstring in valuesArray)
        {
            indx = test.IndexOf(searchstring);
            if (indx > -1)
            {
                testValue = true;
                break;
            }             
        }

Just to be clear, you want to know whether any of the words in someArray are in x, or whether each of the words in someArray are in x? — John Feminella
– John Feminella, Commented Dec 18, 2011 at 22:14

Guffa · Accepted Answer · 2011-12-18 22:14:17Z

2

Loop through the array, and exit as soon as you find a match:

bool found = someArray.Any(s => x.Contains(s));

A non-LINQ version of the same would be:

bool found = false;
foreach (string s in someArray) {
  if (x.Contains(s)) {
    found = true;
    break; // exit from loop
  }
}

answered Dec 18, 2011 at 22:14

Guffa

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1 Comment

Guffa Over a year ago

@thermacore: That is the string that you get from the client, as per your question.

John Feminella · Accepted Answer · 2011-12-18 22:37:10Z

1

You can use the appropriate extension method depending on exactly you want. Suppose that the input string is stored in s, and that the array of words you want to check is wordsToMatch. Then:

... if you want to know whether any of the words match:

var stringMatched = wordsToMatch.Any(w => s.Contains(w));
// true or false

... if you want to know which words match:

var matchingWords = wordsToMatch.Where(w => s.Contains(w));
// ["apple", "ban", "banana", "nana", "coconut", "nut", ...]

... if you want to know whether each word matches:

var wordMatchResult = wordsToMatch.Select(w => s.Contains(w));
// [true, true, false, true, false, true, ...]

edited Dec 18, 2011 at 22:37

answered Dec 18, 2011 at 22:19

John Feminella

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Comments

sehe · Accepted Answer · 2011-12-18 22:32:47Z

0

The .NET framework has a string.contains method that does what you want to do. Loop through the array. For each item in the array, check if x.Contains(item) is true

http://msdn.microsoft.com/en-us/library/dy85x1sa.aspx

string s1 = "fjdswordslkjf?dkHEYw";
foreach (String s in array)
    b = s1.Contains(Array[item]);  //will be T or F

edited Dec 18, 2011 at 22:32

sehe

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answered Dec 18, 2011 at 22:14

bernie2436

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Comments

DotNetUser · Accepted Answer · 2011-12-18 22:45:10Z

0

    bool CheckForString(string[] someArray,string x)
    {          
      foreach(string s in someArray)
        if(x.contains(s))
          return true;
      return false;
    }

I think "contains" is faster than indexOf()

answered Dec 18, 2011 at 22:45

DotNetUser

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