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Remove item from list of list in Haskell


Remove item from list of list in Haskell

By : Daruis Pusmetris
Date : October 17 2020, 06:10 AM
this one helps. So you can't have removeItem both be Int -> [Int] -> [Int] and Int -> [[Int]] -> [[Int]]. Instead, I'll call the latter removeItem'. You already know how to remove an item from just a regular list, so just use map to do it on a list of those lists. Implementation is then simple:
code :
removeItem' :: Int -> [[Int]] -> [[Int]]
removeItem' x = map (removeItem x)


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Learning Haskell: How to remove an item from a List in Haskell

Learning Haskell: How to remove an item from a List in Haskell


By : user1697730
Date : March 29 2020, 07:55 AM
To fix the issue you can do The others are right that the problem is the : operator. I would say that your areTheySame function that returns a list is the wrong approach anyway, though. Rather than switch to the ++ operator, a better implementation of that function would be:
code :
removeItem _ []                 = []
removeItem x (y:ys) | x == y    = removeItem x ys
                    | otherwise = y : removeItem x ys
Remove an item from a list in Haskell

Remove an item from a list in Haskell


By : Stanislav Kositsyn
Date : March 29 2020, 07:55 AM
I wish this help you How can I delete an item from a list in Haskell? I've got this code but it doesn't seems to work. The concept its, I've got 2 lists, the aList will always have just one element. bList will always have the element that its in aList. So I want to delete the element from bList and at the end, output the new list without that item. Could give some hints please?
code :
removeFromList :: Eq a => [a] -> [a] -> [a]
removeFromList _ []           = []
removeFromList (y:ys) (x:xs)
                  | y == x = removeFromList [y] xs
                  | otherwise = x : removeFromList [y] xs
removeFromList _ [] = []
Select item from a drop down list, remove item from list as a value then update a total

Select item from a drop down list, remove item from list as a value then update a total


By : kyohess
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further I am trying to use asp.net and C# I want to create a variable that has a given value of 10. lets call this variable pool I then want to be able to select a number between 1 and 10 from a dropdownlist. , Is it that hard?
The explanation as per the code comment below
code :
<asp:ScriptManager ID="sm" runat="server"></asp:ScriptManager>
<asp:UpdatePanel ID="up" runat="server" UpdateMode="Conditional">
    <ContentTemplate>
        My Pool : <asp:Label ID="lbl" runat="server" Text="10"></asp:Label><br />
        <asp:HiddenField ID="hf" runat="server" Value="10" />
        <asp:DropDownList ID="ddl" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddl_SelectedIndexChanged"></asp:DropDownList>
    </ContentTemplate>
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="ddl" />
    </Triggers>
</asp:UpdatePanel>
protected void Page_Load(object sender, EventArgs e)
{
    // Check
    if (!IsPostBack)
    {
        // Variable
        DataTable dt = new DataTable();
        dt.Columns.Add("Count");

        // Loop
        for (int i = 0; i < 11; i++)
            dt.Rows.Add(i);

        // Bind to Drop Down
        ddl.DataSource = dt;
        ddl.DataTextField = "Count";
        ddl.DataValueField = "Count";
        ddl.DataBind();

        // Dispose
        dt.Dispose();
    }
}


protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
{
    // Variable
    int myPool = 0;
    int mySelectedValue = 0;
    int result = 0;
    int dropDownValue = 0;
    bool isInteger = false;

    // Parse Integer
    int.TryParse(hf.Value, out myPool);
    int.TryParse(ddl.SelectedValue, out mySelectedValue);

    // Set Result
    result = myPool - mySelectedValue;

    // Set to Hidden Value
    hf.Value = result + "";
    lbl.Text = result + "";

    foreach (ListItem item in ddl.Items)
    {
        // Reset
        isInteger = false;
        dropDownValue = 0;

        // Parse Drop Down Value
        isInteger = int.TryParse(item.Value, out dropDownValue);

        // Check
        if (isInteger)
        {
            // Ensure is not less than 0, If less than 0 disabled the selected value
            if ((result - dropDownValue) < 0)
                item.Enabled = false;
        }
    }
}
jQuery remove item from sortable list AND update list of item ID's left

jQuery remove item from sortable list AND update list of item ID's left


By : john smith
Date : March 29 2020, 07:55 AM
will help you Here is an example of how to do this: https://jsfiddle.net/Twisty/5afo47k1/7/
code :
jQuery(document).ready(function($) {

  $("ul.layers-multi-image-list").sortable({
    placeholder: "ui-state-highlight",
    update: function(event, ui) {
      var ordering = $.map($("> li img", this), function(el) {
        return el.id
      }).join(",");
      $('.image_ids').val(ordering);
    }
  });

  $('ul.layers-multi-image-list').disableSelection();

  $("ul.layers-multi-image-list").on('click', '.layers-multi-image-remove', function() {
    var imgId = $(this).parent().find("img").attr("id");
    console.log("Removing:", imgId);
    $(this).parent().remove();
    var curList = $('.image_ids').val();
    var st = curList.indexOf(imgId);
    if (st) {
      var end = st + imgId.length;
      console.log("Start: ", st, " End: ", end);
      newList = curList.substring(0, st-1);
      newList += curList.substring(end);
      console.log(newList);
      $('.image_ids').val(newList);
    }
  });
});
var curList = $('.image_ids').val(); // The current List
var st = curList.indexOf(imgId); // Find if needle is in the list
if (st) { // It is, let's remove it, or do nothing
  var end = st + imgId.length; // 4 numbers in ID
  var newList = curList.substring(0, st-1); // Grab the text before
  newList += curList.substring(end); Ammend the text after
  $('.image_ids').val(newList); // Put it back in the text box
}
$("ul.layers-multi-image-list").on('click', '.layers-multi-image-remove', function() {
    var imgId = $(this).parent().find("img").attr("id");
    var curList = $('.image_ids').val();
    console.log("Removing:", imgId, " From: ", curList);
    $(this).parent().remove();
    var st = curList.indexOf(imgId);
    if (st >= 0) {
      var end = st + imgId.length;
      console.log("Start: ", st, " End: ", end);
      var newList = "";
      if (st > 0) {
        newList += curList.substring(0, st - 1);
        newList += curList.substring(end);
      } else {
        newList += curList.substring(end + 1);
      }
      console.log(newList);
      $('.image_ids').val(newList);
    }
  });
Remove or add an item to list in Haskell

Remove or add an item to list in Haskell


By : user3168212
Date : March 29 2020, 07:55 AM
Any of those help I have to design a function removeOrAdd :: a -> [a] -> [a]. My straightforward solution: ,
Is there any function in Haskell that already do it?
code :
removeOrAdd :: Eq a => a -> [a] -> [a]
removeOrAdd x = go
    where go [] = [x]
          go (y:ys) | x == y = ys
                    | otherwise = y : go ys
removeOrAdd :: Ord a => a -> [a] -> [a]
removeOrAdd x = go
    where go [] = [x]
          go (y:ys) | x == y = ys
                    | y > x = x : y : ys
                    | otherwise = y : go ys
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