I am attempting to code a one dimensional array to display code allowing me to display multiples of seven, I'm not sure how to go through with this, thank you.
I hope I understood your question. You can use generate multiples of 7 using Linq as follows.
var result = Enumerable.Range(1, 100).Select(x => x * 7).ToArray();
Enumerable.Range allows you to generate a sequence of values in specified range (First parameter is the first number in sequence, the second parameter is number of items), while the Select statement (x=>x*7, multiply each value in generated sequence with 7) ensures you get the multiples of 7.
Complete Code:
var result = Enumerable.Range(1, 100).Select(x => x * 7).ToArray();
foreach (var item in result)
{
Console.WriteLine(item);
}
Console.ReadLine();
Due to the vagueness of the question, my answer may not be applicable, but I will attempt to answer based on my assumption of what you are asking.
If you have an array of int and you want to multiply the values of the individual array objects, you would do something like this:
int[] myArray= { 3,5,8};
for (int i = 0; i < myArray.Length; i++)
{
Console.WriteLine(myArray[i]*7);
}
//outputs 21,35,56
If you want to multiply based on the index of the array object, you would do it like this:
int[] myArray= { 3,5,8};
for (int i = 0; i < myArray.Length; i++)
{
Console.WriteLine(i*7);
}
//outputs 0,7,14
//or if you need to start with an index of 1 instead of 0
int[] myArray= { 3,5,8};
for (int i = 0; i < myArray.Length; i++)
{
Console.WriteLine((i+1)*7);
}
//outputs 7,14,21
Anu Viswan also has a good answer, but depending on what it is you are trying to do, it may be better to rely on loops. Hope my answer helps.
Related
I am working with Arrays and conditionals statements, little lost right now and was hoping for some input.
So, I created two Arrays
int[] one = new int[] {
4160414, 6610574, 2864453, 9352227, -4750937, -3132620, 2208017,
-2226227, -8415856, -9834062, -3401569, 7581671, 8068562, 7520435,
-9277044, -7821114, -3095212, 966785, 6873349, -8441152, -7015683,
-6588326, -282013, 4051534, 9930123, -3093234 };
int[] two = new int[] {
1099626, 6083415, 8083888, -8210392, 2665304, -8710738, -8708241,
8859200, -1255323, 5604634, 2921294, -7260228, 7261646, 1137004,
5805162, 4883369, 8789460, 9769240, 319012, -7877588, -1573772,
5192333, 1185446, 1302131, 4217472, -3471445};
My next step what i was thinking is i am going to have to loop through each array
for (int i = 0; i < one.Length; i++)
{
int xValue = one[i];
for (int j = 0; j < two.Length; j++)
{
int yValue = two[j];
}
}
Now that i have the index of each Array i need to check wether the index of xValue is less than the index of yValue
if (xValue < yValue)
{
// dO SOMETHING HERE
}
if (yValue < xValue)
{
// Do Something HERE
}
Where i am getting confused at, is with C# from my understanding you can not push new values into an Array, it needs to be a new instance of the array and copy?
So i tried doing
if (xValue < yValue)
{
Array.Copy(one, x, 13);
}
if (yValue < xValue)
{
Array.Copy(two, x, 13)
}
Both Arrays have 26 values, so a new array of 13 would need to be created to insert the checked value, but Array.Copy seems to not be working getting an array out of bounds check lower bounds.
I'm just confused on checking the values of both arrays at their index, then grabbing the smallest value of the checked values then taking that small value and inserting it into a new array, then use a foreach-loop to iterate over it and print the values to the console. FacePalm
You can use LINQ's Zip to achieve this:
int[] smallest = one.Zip(two, (o, t) => Math.Min(o,t)).ToArray();
Essentially, Zip will provide both items to the lambda expression, allowing you to combine them how you see fit. In this case, we just choose the minimum and return it.
Try it online
Basically, you need to define the size of the new array when you declare it. Make it the same size as one. Then add the smallest item from one or two on each iteration by comparing the items in each array at index i.
int[] smallest = new int[one.Length];
for (int i = 0; i < one.Length; i++)
{
if (one[i] < two[i])
{
smallest[i] = one[i];
}
else
{
smallest[i] = two[i];
}
}
I have classic find duplicate algorithm like this:
int n = int.Parse(Console.ReadLine());
Console.WriteLine();
List<int> tempArr = new List<int>();
List<int> array = new List<int>();
for (int i = 0; i < n; i++)
{
Console.Write("input number {0}: ", i + 1);
tempArr.Add(int.Parse(Console.ReadLine()));
}
tempArr.Sort();
for (int i = 0; i < n; i++)
{
for (int j = i+1; j < n; j++)
{
if (tempArr[i] == tempArr[j])
{
array.Add(tempArr[i]);
}
}
}
Everything work's okay, but if i have just two duplicate numbers like (1,2,2,3,4,5) how can i add them both to List<int> **array** with one clean shot at the loop ?
Instead of lists you could use some kind of data structure that have a better search capability (hash tables or binary trees, for example). Even if you have just one duplicate, the problem is that you need to check if you have already added the element in the list, so the key operation in your algorithm is the search. The faster you perform the search, the faster the algorithm will be. Using binary search, which is the fastest way to search, you get O(nlogn) (you perform n searches of O(logn)).
An even better way to do this is to have some kind of array that has the same size as your input range and "tick" each value that you already have. This search runs in constant time, but gets inefficient if you have a large range of input.
You can use distinct:
array = tempArr.Distinct().ToList();
Distinct isn't in linear time, if that's what you're looking for ("one clean shot"). If you know more about the input you might be able to find a way to do this in linear time. For example, if you know if the integers you take are in a certain range.
To extract all the duplicates you can use Linq:
List<int> tempList = new List<int>() { 1, 2, 2, 3, 4, 5 };
// array == [2, 2]
List<int> array = tempList
.GroupBy(x => x)
.Where(x => x.Count() > 1)
.SelectMany(x => Enumerable.Repeat(x.Key, x.Count()))
.ToList();
I am working on a game in c# but that detail is not really neccessary to solve my problem.
At I high level here is what I want:
I have a set that could have any number of items in it.
I want to randomly select 10 items from that set.
If the set has less than 10 items in then I expect to select the same
item more than once.
I want to ensure every item is selected at least once.
What would be the algorithm for this?
Sorry I'm not sure if this is an appropriate place to ask, but I've got no pen and paper to hand and I can't quite get my head round what's needed so appreciate the help.
In addition I might also want to add weights to the items to
increase/decrease chance of selection, so if you are able to
incorporate that into your answer that would be fab.
Finally thought I should mention that my set is actually a List<string>, which might be relevent if you prefer to give a full answer rather than psuedo code.
This is what I use to randomize an array. It takes an integer array and randomly sorts that list a certain amount of times determined by the random number (r).
private int[] randomizeArray(int[] i)
{
int L = i.Length - 1;
int c = 0;
int r = random.Next(L);
int prev = 0;
int curr = 0;
int temp;
while (c < r)
{
curr = random.Next(0, L);
if (curr != prev)
{
temp = i[prev];
i[prev] = i[curr];
i[curr] = temp;
c++;
}
}
return i;
}
If you look for effective code, my answer isnt it. In theory, create some collection you can remove from that will mirror your set. Then select random member of the object from it ...and remove, this will garantee items wont repeat(if possible).
Random rnd = new Random();
List<int> indexes = new List<int>(items.Count);
for (int i = 0; i < items.Count; i++)
indexes.Add(i);
List<string> selectedItems = new List<string>(10);
int tmp;
for(int i = 0; i < 10; i++)
{
tmp = rnd.Next(1,10000); //something big
if(indexes.Count > 0)
{
selectedItems.Add(yourItems[indexes[tmp%indexes.Count]]);
indexes.RemoveAt(tmp%indexes.Count);
}
else
selectedItems.Add(yourItems[rnd.Next(0,9)]); //you ran out of unique items
}
where items is your list and yourItems is list of selected items, you dont need to store them if you want process them right away
Perhaps shuffle the collection and pick elements from the front until you have the required amount.
Once you've gone through all the elements, you should perhaps shuffle it again, so you don't just repeat the same sequence.
The basic algorithm for shuffling: (in pseudo-code)
for i from n − 1 downto 1 do
j ← random integer with 0 ≤ j ≤ i
exchange a[j] and a[i]
With the above algorithm (or a minor variation), it's possible to just shuffle until you reach the required number of elements, no need to shuffle the whole thing.
I have 2 arrays, first array holds all the values for resource_wastage and 2nd array holds all the value for power_consumed. To implement a fuzzy logic I need to check of both resource wastage and power consumption are low at the same time then my output would be the array index, if one of them is low and second is not then I should move on to the next value in the array.
Eg:
for(int i=0, i<n; i++)
if(res_was[0] is low in all res_was[i=0 to n] && [pow_con[0] is low in all pow_con[i=0 to n])
{
print i;
break;
}
else continue with next value in arrays;
Please help how to I implement this, I mean check if the values in both arrays are low simultaneously.
You can use something like this. Arrays have special method for Min search.
var resMin = res_was.Min();
var powMin = pow_con.Min();
for(int i = 0; i < n; i++)
{
if(res_was[i] == resMin && pow_con[i] == powMin)
{
Console.writeLine(i);
break;
}
}
May be you will need use more complex Min method. You can read about all of them in MSDN.
Also try this;
find the minvalue and minvalue position then compare if equal proceed your process...
int _ires_wasminValue = Enumerable.Range(0, res_was.Length).Min(i => res_was[i]);
int _imin_res_was_pos = Array.IndexOf(res_was, _ires_wasminValue);
int _ipow_cons_minValue = Enumerable.Range(0, res_was.Length).Min(i => res_was[i]);
int _imin_pow_cons_pos = Array.IndexOf(res_was, _ires_wasminValue);
if (_imin_pow_cons_pos==_imin_res_was_pos)
{
Console.writeLine(_imin_pow_cons_pos);
}
In my code i have an arraylist called array.
I have filled it with numbers from 1 to 13
for(int i =1; i< 14; i++)
{
array.items.Add(i)
}
Later in my code I also remove some of the elements at random.
Example array.remove(3);
Now I wanna search, how many values of the elements
in the arraylist is over specific number.
So, how many elements in the arraylist is over for example 5.
Anyone who knows how to do this?
Thanks!
Use this lambda expression:
int count = array.Cast<int>().Where(e=> e > 5).Count();
or even simpler:
int count = array.Cast<int>().Count(e=> e > 5);
You must be from Java right? I believe that you should use a List<T> in c#.
int count = array.Cast<int>().Count(x => x > 5);
OR change your arrayList to be an enumerable to allow.
int count = array.Count(x => x > 5);
array.Cast<int>().Where(item => item > 5).Count();