CODEWITHSUNDEEP
c#arrayslist
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Reputation: 1622

Find the index in an array of lists

I have a following array. I would like to find the index of the array which has M in the list so it should give me 2.

 Array    List
    0 - > B, P , C
    1 - > U, O, L
    2 - > I, N, M

List<string>[] final = new List<string>[3];

I tried the following:

Array.IndexOf(final,"M")

But it does not work and it returns - 1 because second parameter is a list. Please do not use Linq

Upvotes: 1

Views: 66

Answers (4)

user10996922
user10996922

Reputation:

Keep in mind that you have a List<string> at each index of the array named final, so you just can't use Array.IndexOf, you have to search for the Key separately at every index. Following code is the working example of what you want to achieve:

public static int SearchKey(List<string>[] array, string key)
{
    int index = 0;
    foreach(List<String> i in array)
    {
        if(i.Contains(key))
        {
            return index;
        }
        index++;
    }
    return -1;
}

Upvotes: 0

TheGeneral
TheGeneral

Reputation: 81573

Just put some alternatives, if you wanted to ditch the array you could achieve the following with standard Linq methods 

 var final = new List<List<string>>();

 var item = final.FirstOrDefault(x => x.Contains("M"));
 // do stuff with item result

 var index = final.FindIndex(x => x.Contains("M"));
 // do stuff with the index

Upvotes: 0

Anu Viswan
Anu Viswan

Reputation: 18163

Since your "item to search" is a sub item of the list, you would first need to search each list.This can be done with Linq. Combining the result of Linq Query with Array.IndexOf, you can find the result as

var result  =  Array.IndexOf(final,final.FirstOrDefault(x => x.Contains(searchString)));

Upvotes: 0

StaticBeagle
StaticBeagle

Reputation: 5185

Array.IndexOf will traverse the one dimensional array and never find the search string since it will be comparing it to List<string>. You will have to traverse through the list of strings in you array:

public static int FindLetter(IList<string>[] arr, string search)
{
    for(int i = 0; i < arr.Length; ++i)
    {
        if(arr[i].Contains(search)) 
        {
            return i;
        }
    }
    return -1;
}

Upvotes: 1

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