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    <p>OK, so let's break this down.</p> <p>If you're only interested in a normal list of ints, you've got</p> <pre><code> findPosition :: [Int] -&gt; [Int] </code></pre> <p>How can you implement that? Well, uh, you need an input for the thing you're actually searching for!</p> <pre><code> findPosition :: Int -&gt; [Int] -&gt; [Int] </code></pre> <p>OK, cool. So the built-in <code>elem</code> function tells you <em>if</em> the element you want is there. But we want it's <em>position</em>. So how? Well, you can "label" every element with it's position, like so:</p> <pre><code> label :: [x] -&gt; [(Int, x)] label = zip [0..] </code></pre> <p>Now we can use <code>filter</code> to find all the items:</p> <pre><code> find :: (Eq x) =&gt; x -&gt; [(Int, x)] -&gt; [(Int, x)] find x0 = filter (\ (n, x) -&gt; x == x0) </code></pre> <p>But we only want the actual positions, not the <code>x</code>s (which are all identical at this point). So we can <code>map fst</code> to get that.</p> <p>Assembling it all,</p> <pre><code> findPosition :: Int -&gt; [Int] -&gt; [Int] findPosition x0 = map fst . filter (\ (n, x) -&gt; x == x0) . zip [0..] </code></pre> <hr> <p>That's great! But you wanted a list <em>of lists</em> of ints, right?</p> <p>I would suggest you change your requirement spec to return each "coordinate" as a tuple rather than a list. That is, make it so</p> <pre><code>findPosition 8 [[1,2,8],[4,5,6],[7,8,9]] =&gt; [(1, 3), (3, 2)] </code></pre> <p>It's probably less confusing that way. Hopefully I've given you enough hints to figure things out from here...</p>
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    1. POfinding the position of an element from a list of list
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    1. COCheck this pls: findPosition :: Int -> [Int] -> [Int] findPosition x0 = map fst . filter (\ (n, x) -> x == x0) . zip [0..] The function does take only one argument but you define two. It cant compile
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    2. COIt runs for me...
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    3. COIn this case the second argument can be omitted, because the result of composing the functions via (.) is itself a function that takes a single parameter. Another example would be 'add x y = x + y' which is the same as 'add x= (+) x' or 'add x = (x +)'
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