C#•2y ago

✅ how to know the index of repeated items in list ?

I have an list with repeated values i want to know the index of this values ! P.S i will not delete this repeated values

14 Replies

Thinker•2y ago

A simple approach would be something like this

static void List<int> GetIndicies<T>(List<T> items, T value)
{
    List<int> indicies = new();
    
    for (int i = 0; i < items.Count; i++)
    {
        if (items[i].Equals(value)) indicies.Add(i);
    }
    
    return indicies;
}

static void List<int> GetIndicies<T>(List<T> items, T value)
{
    List<int> indicies = new();
    
    for (int i = 0; i < items.Count; i++)
    {
        if (items[i].Equals(value)) indicies.Add(i);
    }
    
    return indicies;
}

Sam DZOP•2y ago

@Diddy yes and i will take that index to print them When i use loop and compare with the value they stuck at first item @🌈 Thinker 🌈 I'm not understanding the code !

Thinker•2y ago

It creates a generic static method GetIndicies which takes a generic list and a value, then it loops through each of the items in the list. If the item at the current index is equal to the item which was passed into the method, then it adds the index to a list. Finally it returns the list of indicies. If you haven't encountered generic methods (<T>) before, then I'd suggest reading up on generics.

Nora•2y ago

List<int> indicies = new();

List<int> indicies = new();

Wow, I didn't know we could write it this way

Thinker•2y ago

It's the same thing as List<int> indicies = new List<int>();, just shorter. Alternatively you can write var indicies = new List<int>();

Nora•2y ago

Is it a good practice?

Thinker•2y ago

Makes your code shorter

Nora•2y ago

Seems like it would save some efforts editing the names/types when you need a change Thanks!

Sam DZOP•2y ago

Can i use .IndexOf(,) ? With loop @🌈 Thinker 🌈 It work ! Lol @🌈 Thinker 🌈 But give me out of range ! I will capture it to see how we can solve it

Sam DZOP•2y ago

Thinker•2y ago

Since you're setting index to ddate.IndexOf(d, x), then the likely thing is that ddate does not contains the value d, and therefore index is set to -1, which causes the exception.

Sam DZOP•2y ago

I put them inside try & catch And worked fine ! Lol Thank you @🌈 Thinker 🌈

Thinker•2y ago

That's just ignoring the issue but sure

Sam DZOP•2y ago

Yes exactly that what i do lol The deadline is today and I don't have time to fix it

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✅ how to know the index of repeated items in list ?