I am trying to sort a list with reference to another list. Consider this example,
var array1 = [1,2,3,4,5,6];
var array2 = [4,6,3];
Now, I want the result to be like this,
result = [4,6,3,1,2,5];
How can I achieve this result?
how about
var array1 = [1,2,3,4,5,6];
var array2 = [4,6,3];
var result = [...array2.where((i) => array1.contains(i)), ...array1.where((i) => !array2.contains(i))];
print('resulting array: ${result}');
The first part collects everything in array2 that lives in the first array, the second part collect everything not in the second array aka the missing values
<script>
var array1 = [1,2,3,4,5,6];
var array2 = [4,8,3];
var sayac=1;
for(var i=0;i<array2.length;i++){
if(array1.indexOf(array2[i])==-1){
array1[array1.length+sayac]=array2[i];
sayac++;
}
}
console.log(array1);
</script>
Related
I am wanting to perform the concatenation as shown below in the objConcat variable but for X number of objects. Sometimes I'll need to concatenate two objects, and sometimes I'll need to concatenate 50 objects.
How can I iterate this in a For loop where I don't have to manually create these individual object variables?
The importData() function returns an object.
var obj1 = importData(0);
var obj2 = importData(1);
var obj3 = importData(2);
var objConcat = obj1.concat(obj2).concat(obj3);
You could get the first data and save it in a variable. Then, loop through the rest and concatenate each of it to the initial variable.
var objConcat = importData(0);
var n = 50;
for (var i=1; i<n; i++) {
objConcat = objConcat.concat(importData(i));
}
I have the following data structure:
Dictionary<string, Dictionary<string, List<int>>> data =
new Dictionary<string, Dictionary<string, List<int>>>();
I want to filter some of the elements in that dictionary based on value in first element of the list of the inner dictionary.
for example:
{legion1
{soldier1, [10,1000]},
{soldier2, [50,1000]}
}
Now let's say I want to do foreach loop in which to work only elements where
the value of the first element of the list is less than 20
expected result in the foreach loop is:
{legion1{soldier1, [10,1000]}}
What I've tried:
I do foreach loop and then I want to use something similar:
data.where(x => x.value.where(o => o[0] < 20 ))
I always get error that that way is incorrect.
Please tell how can I solve the issue and why my way is failing.
You can filter and iterate over the result set like so:
var resultSet =
data.ToDictionary(e => e.Key,
e => e.Value.Where(x => x.Value[0] < 20)
.ToDictionary(k => k.Key, v => v.Value)
);
foreach(var item in resultSet){
var key = item.Key; // string
var values = item.Value; // Dictionary<string, List<int>>
...
...
}
The problem is that you are applying operator [] incorrectly. Moreover, since you want to use both Legion and Soldier, you should construct a tuple combining the two of them:
foreach (var t in data.SelectMany(lg => lg.Value.Select(s => new {
Legion = lg
, Soldier = s
})).Where(ls => ls.Soldier.Value[0] < 20)) {
Console.WriteLine("Legion={0} Soldier = {1}", t.Legion.Key, t.Soldier.Key);
}
I'm trying to concat the selected items from 2 grids in to an array for further processing but I don't want to affect any change in either data source and this is proving problematic as the first data source seems to (after the concat) contain the items I pull from the first ...
var allItems = JSLINQ(grid1.data("kendoGrid").dataSource.data())
.Concat(grid2.data("kendoGrid").dataSource.data())
.ToArray();
the source code for the concat function in JSLINQ is doing this ...
Concat: function (array) {
var arr = array.items || array;
return new JSLINQ(this.items.concat(arr));
}
this.items is from what I can tell the value of "grid1.data("kendoGrid").dataSource.data()"
and i'm trying to build a new array with the items in "grid2.data("kendoGrid").dataSource.data()" which I then intend to filter based on selection criteria.
does anyone have any experience with this / a means to say "I want a copy of the data item from the source that's not connected to the source"?
UPDATE:
The base functionality here relies on having a standard JS array, it seems that kendo returns an observable array object (specific to kendo, and missing the concat function).
The implementation above results in an exception on the concat call (because it doesn't exist), so I rewrote the function to something like this ...
Concat: function (array) {
//var arr = array.items || array;
//return new JSLINQ(this.items.concat(arr));
var retVal = new Array();
for (var i = 0; i < this.items.length; i++) {
var clone = JSON.parse(JSON.stringify(this.items[i]));
retVal.push(clone);
}
for (var i = 0; i < array.length; i++) {
var clone = JSON.parse(JSON.stringify(array[i]));
this.items.push(clone);
}
return new JSLINQ(retVal);
},
That results in the duplicate problem I mentioned above.
So it seems that the error I have here is something to do with observable array, but I don't know how to get a "detatched item" / "array" from the data source.
Ok so it turns out the toJSON() method on an observable array turns the observable array in to an array (odd naming, but hey this is kendo right!)
In short, by manipulating my call input to the JSLINQ method to include this I then have normal JS behaviour as I would expect ...
var allItems = JSLINQ(grid1.data("kendoGrid").dataSource.data().toJSON())
.Concat(grid2.data("kendoGrid").dataSource.data().toJSON())
.ToArray();
I need to know if the List I am working with contains only some specific values.
var list = new List<string> { "First", "Second", "Third" };
If I want to know if the List contain at least one item with the value "First" I use the Any keyword:
var result = list.Any(l => l == "First");
But how I can write a Linq expression that will return true/false only if the List contains "First" and "Second" values?
I'm not entirely sure what you want, but if you want to ensure that "First" and "Second" are represented once, you can do:
var result = list.Where(l => l == "First" || l =="Second")
.Distinct()
.Count() == 2;
or:
var result = list.Contains("First") && list.Contains("Second");
If you've got a longer "whitelist", you could do:
var result = !whiteList.Except(list).Any();
On the other hand, if you want to ensure that all items in the list are from the white-list and that each item in the white-list is represented at least once, I would do:
var set = new HashSet(list);
set.SymmetricExceptWith(whiteList);
var result = !set.Any();
EDIT: Actually, Jon Skeet's SetEquals is a much better way of expressing the last bit.
Your question is unclear.
From the first sentence, I'd expect this to be what you're after:
var onlyValidValues = !list.Except(validValues).Any();
In other words: after you've stripped out the valid values, the list should be empty.
From the final sentence, I'd expect this:
var validSet = new HashSet<string>(requiredValues);
var allAndOnlyValidValues = validSet.SetEquals(candidateSequence);
Note that this will still be valid if your candidate sequence contains the same values multiple times.
If you could clarify exactly what your success criteria are, it would be easier to answer the question precisely.
You can use Intersect to find matches:
var list = new List<string> { "First", "Second", "Third" };
var comparelist = new List<string> { "First", "Second" };
var test = list.Intersect(comparelist).Distinct().Count() == comparelist.Count();
How can I join 2 lists of equal lengths (to produce a 3rd list of equal length) where I do not want to specify a condition but simply rely on the order of items in the 2 lists.
Eg how can I join:
{1,2,3,4} with {5,6,7,8}
to produce:
{{1,5}, {2,6}, {3,7}, {4,8}}
I have tried the following:
from i in new []{1,2,3,4}
from j in new []{5,6,7,8}
select new { i, j }
but this produces a cross join. When I use join, I always need to specify the "on".
You could use Select in the first list, use the item index and access the element on the second list:
var a = new [] {1,2,3,4};
var b = new [] {5,6,7,8};
var qry = a.Select((i, index) => new {i, j = b[index]});
If you are using .Net 4.0, you can use the Zip extension method and Tuples.
var a = new [] {1,2,3,4};
var b = new [] {5,6,7,8};
var result = a.Zip(b, (an, bn) => Tuple.Create(an, bn));
Alternatively, you can keep them as arrays:
var resultArr = a.Zip(b, (an, bn) => new []{an, bn});
There is a half way solution, if you want to use query syntax. Half way in the sense that you need to use the Select method on both lists in order to get the indexes that you will use in the where clause.
int[] list1 = {1,2,3,4};
int[] list2 = {5,6,7,8};
var result = from item1 in list1.Select((value, index) => new {value, index})
from item2 in list2.Select((value, index) => new {value, index})
where item1.index == item2.index
select new {Value1 = item1.value, Value2 = item2.value};
The benefit with this solution is that it wont fail if the lists have different lengths, as the solution using the indexer would do.