I have two string lists en and en1
List<string> en = new List<string>(new string[] { "horse", "cat", "dog", "milk", "honey"});
List<string> en1 = new List<string>(new string[] { "horse1", "cat2", "dog3", "milk4", "honey5" });
And I want radomize their content "Shuffle them" and put this radomized content to new two lists.
But I also want them randomize same way so lists after randomization will still be
en[0] == en1[0]
random content after randomization
{ "cat", "horse", "honey", "milk", "dog"}
{ "cat2", "horse1", "honey5", "milk4", "dog3"}
Two obvious ways:
Take a normal shuffle method, and change it to modify both lists at the same time
Transform the two lists into a single joint list, shuffle that, then split them again
The second sounds cleaner to me. You'd use something like:
var joined = en.Zip(en1, (x, y) => new { x, y }).ToList();
var shuffled = joined.Shuffle(); // Assume this exists
en = shuffled.Select(pair => pair.x).ToList();
en1 = shuffled.Select(pair => pair.y).ToList();
Third obvious way:
Shuffle a list of integers 0, 1, ... , Count-1 and use this list as indexes into the original lists.
Edit
This goes along this lines (for user38...):
List<int> shuffeledIndex = new List<int>();
for(int i = 0; i < en.Count; i++) shuffeledIndex.Add(i);
shuffeledIndex.Shuffle(); // Assume this exists
enshuffeled = en[shuffeledIndex[i]]; // instead en[i]
en1shuffeled = en1[shuffeledIndex[i]];
Adding to Jon Skeet's answer, a nice way to do the shuffling is OrderBy(x => Guid.NewGuid()) so the code would look like
var joined = en.Zip(en1, (x, y) => new { x, y });
var shuffled = joined.OrderBy(x => Guid.NewGuid()).ToList();
en = shuffled.Select(pair => pair.x).ToList();
en1 = shuffled.Select(pair => pair.y).ToList();
Well, I think #Jon Skeet's answer is better than mine (since I only know the basics about C# and probably for some other reasons... :P), however you could shuffle your lists manually with something like this:
for(int i=0;i<en.Count;i++) {
int remainingCount = en.Count - 1;
int exchangeIndex = i + (new Random()).nextInt(0, remainingCount);
swap(en, i, exchangeIndex);
swap(en1, i, exchangeIndex);
}
Of course you would need to write a swap function like swap(List<string> list, int indexA, int indexB):
string tmp = list[indexA];
list[indexA] = list[indexB];
list[indexB] = tmp;
You could first combine the two lists into one using the Zip function:
var zipped = en.Zip(en1, (first, second) => new { first, second }).ToList();
You'll then need a shuffling function to shuffle them. You could use the Fisher–Yates shuffle in an extension method:
public static void FisherYatesShuffle<T>(this IList<T> list)
{
var rnd = new Random();
var x = list.Count;
while (x > 1) {
x--;
var y = rnd.Next(x + 1);
T value = list[y];
list[y] = list[x];
list[x] = value;
}
}
To use the extension method:
var shuffled = zipped.FisherYatesShuffle();
Now you can split them back out again into two separate lists:
en = shuffled.Select(combined => combined.x).ToList();
en1 = shuffled.Select(combined => combined.y).ToList();
Related
I have a constructor which uses a List parameter. Inside that list I have three items which are 3 integer arrays.
public HistogramLogic(List<Tuple<int[], int[], int[]>> separateRGB)
Now I want to initialize three new integer arrays with the arrays inside that list. But when I try this code, the index of my new arrays stay 0.
for (int i = 0; i < histogramXValues.Length; i++)
{
rArray = separateRGB.Select(obj => obj.Item1[i]).ToArray();
gArray = separateRGB.Select(obj => obj.Item2[i]).ToArray();
bArray = separateRGB.Select(obj => obj.Item3[i]).ToArray();
}
Anyone got any suggestions on how to fix this?
Bear in mind, if you have a list of N tuples, you start with 3 x N arrays. Sounds like you want them combined into 3 arrays, each containing all of the elements throughout the list. Which you can do with SelectMany.
rArray = separateRGB.SelectMany(obj => obj.Item1).ToArray();
gArray = separateRGB.SelectMany(obj => obj.Item2).ToArray();
bArray = separateRGB.SelectMany(obj => obj.Item3).ToArray();
Full example:
using System;
using System.Linq;
using System.Collections.Generic;
public class Program
{
static public void HistogramLogic(List<Tuple<int[], int[], int[]>> separateRGB)
{
var rArray = separateRGB.SelectMany(obj => obj.Item1).ToArray();
var gArray = separateRGB.SelectMany(obj => obj.Item2).ToArray();
var bArray = separateRGB.SelectMany(obj => obj.Item3).ToArray();
Console.WriteLine("rArray = {{{0}}}", string.Join(",", rArray));
Console.WriteLine("gArray = {{{0}}}", string.Join(",", gArray));
Console.WriteLine("bArray = {{{0}}}", string.Join(",", bArray));
}
public static void Main()
{
var mockData = new List<Tuple<int[], int[], int[]>>
{
Tuple.Create(new[] {11,12,13}, new[] {14,15,16}, new[] {17,18,19}),
Tuple.Create(new[] {21,22,23}, new[] {24,25,26}, new[] {27,28,29}),
Tuple.Create(new[] {31,32,33}, new[] {34,35,36}, new[] {37,38,39})
};
HistogramLogic(mockData);
}
}
Output:
rArray = {11,12,13,21,22,23,31,32,33}
gArray = {14,15,16,24,25,26,34,35,36}
bArray = {17,18,19,27,28,29,37,38,39}
Click here for code on DotNetFiddle
You can just get the item from touple
rArray = separateRGB.Select(obj => obj.Item1);
Like they sad in comments you did reassign local member in each loop.
You could use something like this.
public HistogramLogic(List<Tuple<int[], int[], int[]>> separateRGB)
{
List<int> rList = new List<int>();
List<int> gList = new List<int>();
List<int> bList = new List<int>();
separateRGB.ForEach((Tuple<int[], int[], int[]> tpl) =>
{
rList.AddRange(tpl.Item1);
gList.AddRange(tpl.Item1);
bList.AddRange(tpl.Item1);
});
rArray = rList.ToArray();
gArray = gList.ToArray();
bArray = bList.ToArray();
}
If you wish to not use temp List object you should know final count of elements in tuple, create local array member to desired size. and fill it. List are more suitable for adding and expanding elements. Maybe you could use one Linq Statement but if I understand goal is to get one int[] array per color. If you take
separateRGB.AsQueryable().Select(m => m.Item1).ToArray();
as a result you get int[][] result instead of simple int array;
I have a text file that contains Values in this Format: Time|ID:
180|1
60 |2
120|3
Now I want to sort them by Time. The Output also should be:
60 |2
120|3
180|1
How can I solve this problem? With this:
var path = #"C:\Users\admin\Desktop\test.txt";
List<string> list = File.ReadAllLines(path).ToList();
list.Sort();
for (var i = 0; i < list.Count; i++)
{
Console.WriteLine(list[i]);
}
I got no success ...
3 steps are necessary to do the job:
1) split by the separator
2) convert to int because in a string comparison a 6 comes after a 1 or 10
3) use OrderBy to sort your collection
Here is a linq solution in one line doing all 3 steps:
list = list.OrderBy(x => Convert.ToInt32(x.Split('|')[0])).ToList();
Explanation
x => lambda expression, x denotes a single element in your list
x.Split('|')[0] splits each string and takes only the first part of it (time)
Convert.ToInt32(.. converts the time into a number so that the ordering will be done in the way you desire
list.OrderBy( sorts your collection
EDIT:
Just to understand why you got the result in the first place here is an example of comparison of numbers in string representation using the CompareTo method:
int res = "6".CompareTo("10");
res will have the value of 1 (meaning that 6 is larger than 10 or 6 follows 10)
According to the documentation->remarks:
The CompareTo method was designed primarily for use in sorting or alphabetizing operations.
You should parse each line of the file content and get values as numbers.
string[] lines = File.ReadAllLines("path");
// ID, time
var dict = new Dictionary<int, int>();
// Processing each line of the file content
foreach (var line in lines)
{
string[] splitted = line.Split('|');
int time = Convert.ToInt32(splitted[0]);
int ID = Convert.ToInt32(splitted[1]);
// Key = ID, Value = Time
dict.Add(ID, time);
}
var orderedListByID = dict.OrderBy(x => x.Key).ToList();
var orderedListByTime = dict.OrderBy(x => x.Value).ToList();
Note that I use your ID reference as Key of dictionary assuming that ID should be unique.
Short code version
// Key = ID Value = Time
var orderedListByID = lines.Select(x => x.Split('|')).ToDictionary(x => Convert.ToInt32(x[1]), x => Convert.ToInt32(x[0])).OrderBy(x => x.Key).ToList();
var orderedListByTime = lines.Select(x => x.Split('|')).ToDictionary(x => Convert.ToInt32(x[1]), x => Convert.ToInt32(x[0])).OrderBy(x => x.Value).ToList();
You need to convert them to numbers first. Sorting by string won't give you meaningful results.
times = list.Select(l => l.Split('|')[0]).Select(Int32.Parse);
ids = list.Select(l => l.Split('|')[1]).Select(Int32.Parse);
pairs = times.Zip(ids, (t, id) => new{Time = t, Id = id})
.OrderBy(x => x.Time)
.ToList();
Thank you all, this is my Solution:
var path = #"C:\Users\admin\Desktop\test.txt";
List<string> list = File.ReadAllLines(path).ToList();
list = list.OrderBy(x => Convert.ToInt32(x.Split('|')[0])).ToList();
for(var i = 0; i < list.Count; i++)
{
Console.WriteLine(list[i]);
}
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class TestClass {
public static void main(String[] args) {
List <LineItem> myList = new ArrayList<LineItem>();
myList.add(LineItem.getLineItem(500, 30));
myList.add(LineItem.getLineItem(300, 20));
myList.add(LineItem.getLineItem(900, 100));
System.out.println(myList);
Collections.sort(myList);
System.out.println("list after sort");
System.out.println(myList);
}
}
class LineItem implements Comparable<LineItem>{
int time;
int id ;
#Override
public String toString() {
return ""+ time + "|"+ id + " ";
}
#Override
public int compareTo(LineItem o) {
return this.time-o.time;
}
public static LineItem getLineItem( int time, int id ){
LineItem l = new LineItem();
l.time=time;
l.id=id;
return l;
}
}
I have the following code:
Dictionary<int, List<PointF>> dictEntities = new Dictionary<int, List<PointF>>();
dictEntities.Add(1, new List<PointF>() { new PointF(1.0F, 2.0F), new PointF(3.0F, 4.0F) });
dictEntities.Add(2, new List<PointF>() { new PointF(3.0F, 4.0F), new PointF(1.0F, 2.0F) });
dictEntities.Add(3, new List<PointF>() { new PointF(7.0F, 8.0F), new PointF(9.0F, 6.0F) });
I want to remove the dictionary entries which lists are duplicates.
Expected result after the duplicates have been removed: The dictionary now contains 2 entries (either "1" and "3" or "2" and "3") because entry 1 and 2 have the same lists of PointF's inside. 1 or 2 gets removed from the dictionary. I think I have to sort the List first then make a distinct on it somehow? But how to I actually delete the entries that are duplicates?
What I have tried so far is this:
foreach (var item in dictEntities.ToList())
{
while (dictEntities.Values.Contains(item.Value))
{
dictEntities.Remove(item.Key);
}
}
But this always empties the whole dictionary. I have to work it out somehow.
Thank you
You could do this with a custom IEqualityComparer and using GroupBy. For example:
public class MyComparer : IEqualityComparer<List<PointF>>
{
public bool Equals(List<PointF> l1, List<PointF> l2)
{
//If lists contain different amount of items, they are different
if(l1.Count() != l2.Count()) return false;
//Order the lists by X then Y, that way we can compare them in order
var orderedL1 = l1.OrderBy(p => p.X).ThenBy(p => p.Y).ToList();
var orderedL2 = l2.OrderBy(p => p.X).ThenBy(p => p.Y).ToList();
for(var i = 0; i < l1.Count(); i++)
{
if(orderedL1[i].X != orderedL2[i].X) return false;
if(orderedL1[i].Y != orderedL2[i].Y) return false;
}
//They must be the same if we reached here
return true;
}
public int GetHashCode(List<PointF> dp)
{
return 0;
}
}
And use it like this:
var distinctList = dictEntities
.GroupBy(de => de.Value, new MyComparer())
.Select(de => de.Key);
If you want to keep it as a dictionary, instead of Select, use ToDictionary and take your pick of method to choose the key. Here is an example using First (which means you will get items 1 and 3 from your example):
var distinctList = dictEntities
.GroupBy(de => de.Value, new MyComparer())
.ToDictionary(g => g.First().Key, g => g.Key);
I have 3 arrays.
Array 1 = {1,1,1,1,2,2,3,3}
Array 2 = {a,a,a,a,e,e,b,b}
Array 3 = {z,z,z,z,z,z,z,z}
I would like to remove all duplicates from array 1 and also remove the same element at said duplicate in the other arrays to keep them all properly linked.
I know you can use .Distinct().ToArray() to do this for one array, but then the other arrays would not have the elements removed as well.
The result would look like this.
Array 1 = {1,2,3}
Array 2 = {a,e,b}
Array 3 = {z,z,z}
I'm guessing the only way to solve this would be the following.
For(int a = 0; a < Array1.count; a++) {
For(int b = a + 1; b < Array1.count; b++) {
if(Array1[a]==Array1[b]) {
Array1.RemoveAt(b);
Array2.RemoveAt(b);
Array3.RemoveAt(b);
}
}
}
Would be nice to find a simple predefined function however!
var distinctIndexes = array1
.Select((item, idx) => new { Item = item, Index = idx })
.GroupBy(p => p.Item)
.Select(grp => grp.First().Index);
var result1 = distinctIndexes.Select(i => array1[i]).ToArray();
var result2 = distinctIndexes.Select(i => array2[i]).ToArray();
var result3 = distinctIndexes.Select(i => array3[i]).ToArray();
Note this won't necessarily use the first unique element from the first array. If you need to do that you can calculate the indexes as
var distinctIndexes = array1
.Select((item, idx) => new { Item = item, Index = idx })
.Aggregate(new Dictionary<int, int>(), (dict, i) =>
{
if (! dict.ContainsKey(i.Item))
{
dict[i.Item] = i.Index;
}
return dict;
})
.Values;
You should consider what data structure you're using carefully. Is this "remove" operation likely to happen all at once? How often? (I'm not challenging your use of Array necessarily, just a general tip, but your scenario seems weird). Also, you did not explain if this is an index-based removal or an element based removal. If I was implementing this, I would be tempted to create a new Array and add all remaining elements to the new Array in a loop, ignoring the elements you want to remove. Then simply reassign the reference with '='. Of course, that depends on the maximum expected size of the Array, since a copy like I suggested would take up more memory (usually wouldn't be a problem).
I don't really know of a clean way to do what you're asking, but this is a generic example of doing what you asked?
static void RemoveDupes(ref Array a1, ref Array a2, ref Array a3)
{
Type a1t, a2t, a3t;
int newLength, ni, oi;
int[] indices;
a1t = a1.GetType().GetElementType();
a2t = a1.GetType().GetElementType();
a3t = a1.GetType().GetElementType();
Dictionary<object, List<int>> buckets = new Dictionary<object, List<int>>();
for (int i = 0; i < a1.Length; i++)
{
object val = a1.GetValue(i);
if (buckets.ContainsKey(val))
buckets[val].Add(i);
else
buckets.Add(val, new List<int> { i });
}
indices = buckets.Where(kvp => kvp.Value.Count > 1).SelectMany(kvp => kvp.Value.Skip(1)).OrderBy(i => i).ToArray();
newLength = a1.Length - indices.Length;
Array na1 = Array.CreateInstance(a1t, newLength);
Array na2 = Array.CreateInstance(a2t, newLength);
Array na3 = Array.CreateInstance(a3t, newLength);
oi = 0;
ni = 0;
for (int i = 0; i < indices.Length; i++)
{
while (oi < indices[i])
{
na1.SetValue(a1.GetValue(oi), ni);
na2.SetValue(a2.GetValue(oi), ni);
na3.SetValue(a3.GetValue(oi), ni);
oi++;
ni++;
}
oi++;
}
while (ni < newLength)
{
na1.SetValue(a1.GetValue(oi), ni);
na2.SetValue(a2.GetValue(oi), ni);
na3.SetValue(a3.GetValue(oi), ni);
oi++;
ni++;
}
a1 = na1;
a2 = na2;
a3 = na3;
}
I have an array of strings like so:
[0]Board1
[1]Messages Transmitted75877814
[2]ISR Count682900312
[3]Bus Errors0
[4]Data Errors0
[5]Receive Timeouts0
[6]TX Q Overflows0
[7]No Handler Failures0
[8]Driver Failures0
[9]Spurious ISRs0
just to clarify the numbers in the square brackets indicate the strings position in the array
I want to convert the array of strings to a dictionary with the string to the left of each number acting as the key, for example (ISR Count, 682900312)
I then want to output specific entries in the dictionary to a text box/table in visual studio (which ever is better) it would be preferable for the numbers to be left aligned.
excuse my naivety, I'm a newbie!
Pretty Simple. Tried and Tested
string[] arr = new string[] { "Board1", "ISR Count682900312", ... };
var numAlpha = new Regex("(?<Alpha>[a-zA-Z ]*)(?<Numeric>[0-9]*)");
var res = arr.ToDictionary(x => numAlpha.Match(x).Groups["Alpha"],
x => numAlpha.Match(x).Groups["Numeric"]);
string[] strings =
{
"Board1", "Messages232"
};
Dictionary<string, int> dictionary = new Dictionary<string, int>();
foreach (var s in strings)
{
int index = 0;
for (int i = 0; i < s.Length; i++)
{
if (Char.IsDigit(s[i]))
{
index = i;
break;
}
}
dictionary.Add(s.Substring(0, index), int.Parse(s.Substring(index)));
}
var stringArray = new[]
{
"[0]Board1",
"[1]Messages Transmitted75877814",
"[2]ISR Count682900312",
"[3]Bus Errors0",
"[4]Data Errors0",
"[5]Receive Timeouts0",
"[6]TX Q Overflows0",
"[7]No Handler Failures0",
"[8]Driver Failures0",
"[9]Spurious ISRs0"
};
var resultDict = stringArray.Select(s => s.Substring(3))
.ToDictionary(s =>
{
int i = s.IndexOfAny("0123456789".ToCharArray());
return s.Substring(0, i);
},
s =>
{
int i = s.IndexOfAny("0123456789".ToCharArray());
return int.Parse(s.Substring(i));
});
EDIT: If the numbers in brackets are not included in the strings, remove .Select(s => s.Substring(3)).
Here you go:
string[] strA = new string[10]
{
"Board1",
"Messages Transmitted75877814",
"ISR Count682900312",
"Bus Errors0",
"Data Errors0",
"Receive Timeouts0",
"TX Q Overflows0",
"No Handler Failures0",
"Driver Failures0",
"Spurious ISRs0"
};
Dictionary<string, int> list = new Dictionary<string, int>();
foreach (var item in strA)
{
// this Regex matches any digit one or more times so it picks
// up all of the digits on the end of the string
var match = Regex.Match(item, #"\d+");
// this code will substring out the first part and parse the second as an int
list.Add(item.Substring(0, match.Index), int.Parse(match.Value));
}