so, quickly. Is it possible to insert a double AND a string into a list? like this:
if (input2 == 0) // this boolean checks if the first number is devided by zero, then:
{
listOfResults.Insert(index: temp, item: "You divided by 0! Wait, thats illegal"); // and thats what i want, to add a string into the position of the list when the input is 0
}
else
{
result = (double)input1 / (double)input2; // the input numbers are int but i cast them to double
listOfResults.Insert(index: position, item: result);
}
My input are : 3 and 2, 6 and 3, -4 and 0, 1 and 2, i devide every first number by the second input number.
The output should be like:
1.5
2
You divided by 0! Wait, thats illegal
0.5
So is it possible to store doubles AND string for each position in List?
Yes, you could make a List< object > which can contain any data type, double, string, int, other objects, etc.
A better option may be to define a Result object such as
class Result
{
public bool Error { get; set; } = false;
public double Value { get; set; }
public string ErrorMessage { get; set; } = "";
}
And then store a list of List< Result > so that you don't need to convert or check types.
You can use a list of tuples:
var tupleList = new List<(double, string)>();
tupleList.Add((2.5, "a string"));
Here's what I'd do given your code:
var listOfResults = new List<(double? result, string error)>();
if (input2 == 0)
{
listOfResults.Insert(index: temp, item: (null, "You divided by 0! Wait, thats illegal"));
}
else
{
result = (double)input1 / input2;
listOfResults.Insert(index: position, item: (result, null));
}
And here's how to print the output:
foreach (var item in listOfResults)
{
if (item.result.HasValue)
Console.WriteLine(item.result);
else
Console.WriteLine(item.error);
}
List will allow both types. You can use typeof() == typeof(double), for instance, when using the values, or simply ToString().
static void Main(string[] args)
{
List<object> myData = new List<object>()
{
1.234,
-0.1,
"divide by zero",
100.0
};
foreach (object item in myData)
{
Console.WriteLine(item.ToString());
}
}
Related
Can anyone please help in build a logic to sort list of string which contains ranged number items.
Ex: List myList = new List() { "1", "3-6", "2", "8-10","7", "11", "13-18", "12"};
Sorted Output List:
1,
2,
3-6,
7,
8-10,
11,
12,
13-18
Note:
List contains only positive numbers.
Thanks,
Arjun
The basics step are:
Convert a string to int
Check if a string contains a separator
Split a String on a separator
Now here is a way to do it:
using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
static void Main(string[] args)
{
var myList = new List<string> { "1", "3-6", "2", "8-10", "7", "11", "13-18", "12" };
var ranges = myList.Select(x=> new Range(x)).ToList();
ranges.Sort();//Order yourself!
//Display
foreach (var range in ranges) Console.WriteLine(range);
//One line with comma separator
Console.WriteLine(string.Join(", ", ranges));
}
public class Range : IComparable<Range>
{
// Simple ctor, with Customisable separator in case of Negative Value.
public Range(string input, char separator= '-') {
if (!input.Contains(separator))// Is it a range?
{//It's not then
if (int.TryParse(input, out int value))// Lets try to convert it to an integer
{// it's a int then
Min = value; Max = value; // both min and max
}
else
{// It's not a range and it's not an int! Scream!
throw new ArgumentException(input + " is not a valid input !");
}
}
else
{//It's a range
var parts = input.Split(new char[] { separator }, 2);// split in 2 on the separator
if (int.TryParse(parts[0], out int part1) && int.TryParse(parts[1], out int part2))// Both part are int?
{
Min = Math.Min(part1, part2); // min is the min and max the max.
Max = Math.Max(part1, part2); // It's easier to compute min/max than try to fix a bad input.
}
else {// It's look like a range but those are not int! Scream!
throw new ArgumentException(input + " is not a valid input !" );
}
}
}
public int Min { get; set; }
public int Max { get; set; }
// Comparing bound together. {1-1} < {1-2} < {1-6} < {2-2};
public int CompareTo(Range obj)
{
var mincomparer = this.Min.CompareTo(obj.Min);
var maxcomparer = this.Max.CompareTo(obj.Max);
return mincomparer == 0 ? maxcomparer : mincomparer;
}
public override string ToString()
{
return Min == Max ? Min.ToString() : Min + "-" + Max;
}
}
}
LiveDemo
I used this question Find out which combinations of numbers in a set add up to a given total which uses a C# example to attempt to find all the possible combinations of numbers which add up to a given number.
I used the code as provided and have attempted to understand it and I think I do, however, I can't figure out why this error is occurring.
Here is the setup:
public class Program
{
public static void Main(string[] args)
{
// subtotal list
List<double> totals = new List<double>(new double[] { 17.5, 14.3, 10.9, 7.8, 6.3, 3.8, 3.2, 2.7, 1.8, 1.0 });
List<double> totals2 = new List<double>(new double[] { 17.5, 14.3, 7.8, 6.3, 3.2, 1.8});
// get matches
List<double[]> results = Knapsack.MatchTotal(50.9, totals2);
// print results`
foreach (var result in results)
{
Console.WriteLine(string.Join(",", result));
}
Console.WriteLine("Done.");
Console.ReadKey();
}
}
and the main bulk of the code is unchanged from the example.
public class Knapsack
{
internal static List<double[]> MatchTotal(double theTotal, List<double> subTotals)
{
List<double[]> results = new List<double[]>();
while (subTotals.Contains(theTotal))
{
results.Add(new double[1] { theTotal });
subTotals.Remove(theTotal);
}
// if no subtotals were passed
// or all matched the Total
// return
if (subTotals.Count == 0)
return results;
subTotals.Sort();
double mostNegativeNumber = subTotals[0];
if (mostNegativeNumber > 0)
mostNegativeNumber = 0;
// if there aren't any negative values
// we can remove any values bigger than the total
if (mostNegativeNumber == 0)
subTotals.RemoveAll(d => d > theTotal);
// if there aren't any negative values
// and sum is less than the total no need to look further
if (mostNegativeNumber == 0 && subTotals.Sum() < theTotal)
return results;
// get the combinations for the remaining subTotals
// skip 1 since we already removed subTotals that match
for (int choose = 2; choose <= subTotals.Count; choose++)
{
// get combinations for each length
IEnumerable<IEnumerable<double>> combos = Combination.Combinations(subTotals.AsEnumerable(), choose);
// add combinations where the sum mathces the total to the result list
results.AddRange(from combo in combos
where combo.Sum() == theTotal
select combo.ToArray());
}
return results;
}
}
public static class Combination
{
public static IEnumerable<IEnumerable<T>> Combinations<T>(this IEnumerable<T> elements, int choose)
{
return choose == 0 ? // if choose = 0
new[] { new T[0] } : // return empty Type array
elements.SelectMany((element, i) => // else recursively iterate over array to create combinations
elements.Skip(i + 1).Combinations(choose - 1).Select(combo => (new[] { element }).Concat(combo)));
}
}
I have provided the set of numbers which is in totals which are used to try and calculate the total.
I entered 50.9 as the total and return no results.
The second set of numbers totals2 is a set of numbers which add up to 50.9 and they are a subset of totals. This also fails to return a result for 50.9
For some reason the code is unable to find 50.9 in the master set or in the subset (which itself sums to 50.9).
I can't figure out why it does this, can anyone tell me?
I'm parsing a CSV file in a c# .net windows form app, taking each line into a class I've created, however I only need access to some of the columns AND the files being taken in are not standardized. That is to say, number of fields present could be different and the columns could appear in any column.
CSV Example 1:
Position, LOCATION, TAG, NAME, STANDARD, EFFICIENCY, IN USE,,
1, AFT-D3, P-D3101A, EQUIPMENT 1, A, 3, TRUE
2, AFT-D3, P-D3103A, EQUIPMENT 2, B, 3, FALSE
3, AFT-D3, P-D2301A, EQUIPMENT 3, A, 3, TRUE
...
CSV Example 2:
Position, TAG, STANDARD, NAME, EFFICIENCY, LOCATION, BACKUP, TESTED,,
1, P-D3101A, A, EQUIPMENT 1, 3, AFT-D3, FALSE, TRUE
2, P-D3103A, A, EQUIPMENT 2, 3, AFT-D3, TRUE, FALSE
3, P-D2301A, A, EQUIPMENT 3, 3, AFT-D3, FALSE, TRUE
...
As you can see, I will never know the format of the file I have to analyse, the only thing I know for sure is that it will always contain the few columns that I need.
My solution to this was to ask the user to enter the columns required and set as strings, the using their entry convert that to a corresponding integer that i could then use as a location.
string standardInpt = "";
string nameInpt = "";
string efficiencyInpt = "";
user would then enter a value from A to ZZ.
int standardLocation = 0;
int nameLocation = 0;
int efficiencyLocation = 0;
when the form is submitted. the ints get their final value by running through an if else... statement:
if(standard == "A")
{
standardLocation = 0;
}
else if(standard == "B")
{
standardLocation = 1;
}
...
etc running all the way to if VAR1 == ZZ and then the code is repeated for VAR2 and for VAR3 etc..
My class would partially look like:
class Equipment
{
public string Standard { get; set;}
public string Name { get; set; }
public int Efficiency { get; set; }
static Equipment FromLine(string line)
{
var data = line.split(',');
return new Equipment()
{
Standard = data[standardLocation],
Name = [nameLocation],
Efficiency = int.Parse(data[efficiencyLocation]),
};
}
}
I've got more code in there but i think this highlights where I would use the variables to set the indexes.
I'm very new to this and I'm hoping there has got to be a significantly better way to achieve this without having to write so much potentially excessive, repetitive If Else logic. I'm thinking some kind of lookup table maybe, but i cant figure out how to implement this, any pointers on where i could look?
You could make it automatic by finding the indexes of the columns in the header, and then use them to read the values from the correct place from the rest of the lines:
class EquipmentParser {
public IList<Equipment> Parse(string[] input) {
var result = new List<Equipment>();
var header = input[0].Split(',').Select(t => t.Trim().ToLower()).ToList();
var standardPosition = GetIndexOf(header, "std", "standard", "st");
var namePosition = GetIndexOf(header, "name", "nm");
var efficiencyPosition = GetIndexOf(header, "efficiency", "eff");
foreach (var s in input.Skip(1)) {
var line = s.Split(',');
result.Add(new Equipment {
Standard = line[standardPosition].Trim(),
Name = line[namePosition].Trim(),
Efficiency = int.Parse(line[efficiencyPosition])
});
}
return result;
}
private int GetIndexOf(IList<string> input, params string[] needles) {
return Array.FindIndex(input.ToArray(), needles.Contains);
}
}
You can use the reflection and attribute.
Write your samples in ,separated into DisplayName Attribute.
First call GetIndexes with the csv header string as parameter to get the mapping dictionary of class properties and csv fields.
Then call FromLine with each line and the mapping dictionary you just got.
class Equipment
{
[DisplayName("STND, STANDARD, ST")]
public string Standard { get; set; }
[DisplayName("NAME")]
public string Name { get; set; }
[DisplayName("EFFICIENCY, EFFI")]
public int Efficiency { get; set; }
// You can add any other property
public static Equipment FromLine(string line, Dictionary<PropertyInfo, int> map)
{
var data = line.Split(',').Select(t => t.Trim()).ToArray();
var ret = new Equipment();
Type type = typeof(Equipment);
foreach (PropertyInfo property in type.GetProperties())
{
int index = map[property];
property.SetValue(ret, Convert.ChangeType(data[index],
property.PropertyType));
}
return ret;
}
public static Dictionary<PropertyInfo, int> GetIndexes(string headers)
{
var headerArray = headers.Split(',').Select(t => t.Trim()).ToArray();
Type type = typeof(Equipment);
var ret = new Dictionary<PropertyInfo, int>();
foreach (PropertyInfo property in type.GetProperties())
{
var fieldNames = property.GetCustomAttribute<DisplayNameAttribute>()
.DisplayName.Split(',').Select(t => t.Trim()).ToArray();
for (int i = 0; i < headerArray.Length; ++i)
{
if (!fieldNames.Contains(headerArray[i])) continue;
ret[property] = i;
break;
}
}
return ret;
}
}
try this if helpful:
public int GetIndex(string input)
{
input = input.ToUpper();
char low = input[input.Length - 1];
char? high = input.Length == 2 ? input[0] : (char?)null;
int indexLow = low - 'A';
int? indexHigh = high.HasValue ? high.Value - 'A' : (int?)null;
return (indexHigh.HasValue ? (indexHigh.Value + 1) * 26 : 0) + indexLow;
}
You can use ASCII code for that , so no need to add if else every time
ex.
byte[] ASCIIValues = Encoding.ASCII.GetBytes(standard);
standardLocation = ASCIIValues[0]-65;
This program add's values with their other values into a dictionary, all is fine until there are identical keys (var eat(.8) and var extra(.8) with different values. How do i ensure that i can use the right key every time even though they are similar? For example, var example = gigantDictionary[.8] (but i want var edmg value instead of '500' in the code?
var wqat = 1.1; //| index 0
var rat = .2; //| index 1
var eat = .8; //| index 2
var baat = 1.2; //| index 3
var extra = .8; //| index 4
var wqdmg = 120; //| index 0
var rdmg = 60; //| index 1
var edmg = 50; //| index 2
var badmg = 40; //| index 3
var extradmg = 500; //| index 4
List<double> theOneList = new List<double>();
List<double> damageList = new List<double>();
theOneList.Add(wqat);
theOneList.Add(rat);
theOneList.Add(eat);
theOneList.Add(baat);
damageList.Add(wqdmg);
damageList.Add(edmg);
damageList.Add(rdmg);
damageList.Add(badmg);
Dictionary<double, double> gigantDictionary = new Dictionary<double, double>();
for (int i = 0; i < theOneList.Count; i++)
{
gigantDictionary.Add(theOneList[i], damageList[i]);
gigantDictionary.Add(extra, 500); //this is the malignant similar key
}
theOneList.Sort((c, p) => -c.CompareTo(p)); //orders the list
List<double> finalList = new List<double>();
for (int i = 0; i < theOneList.Count; i++)
{
finalList.Add(gigantDictionary[theOneList[i]]); //grabs damage values and add's it to 'finalList'
Console.WriteLine(finalList[i]);
}
So ultimately, i want to order 'theOneList' by descent, in doing so i can get the damages from 'gigantDictionary' and put those into 'finalList', now i have an ordered damage list that i need, but since 2 keys are similar... this is holding me back.
*Edit: Could identical indexes be the key to this? be the bridge? for example, in index 0 i get 1.1 and 120, maybe the answer lies with the identical indexes, i want to get '120' damage from '1.1', notice both have index 0, this might work
They keys aren't "similar" they're "identical". If the keys were just "similar" then, as far as the dictionary is concerned, it's no different than being "completely different". From the point of view of a dictionary items are either equal, or not equal.
For example,
var example = gigantDictionary[.8]
(but i want var edmg value instead of '500' in the code?)
But how should the dictionary possibly know that? How would it know if you actually wanted to get 500?
Do you want to prevent the duplicate keys from being added, and instead always use the first value paired with every key? If so, just check if a key exists before adding a new one.
Do you want to just get all values associated with a key, if there are duplicates? Then have a dictionary where the value is a collection, and add all values associated with that one key to the collection.
Is there actually some way to distinguish the keys so that they're not actually identical? Then do that. With just a double (which is a very bad type to use as a key for a dictionary in the first place, as it's easy for floating point rounding errors to result in similar but different doubles that you consider equivalent) there's no good way to do this, but if your actual key could be different in such a way that distinguishes the two keys, then each could point to a unique value.
Right now you have two separate list for values that must go together. A better approach is to create a structure with the two values and keep a single list.
public class Thing
{
public string Name { get; set; }
public double TheOne { get; set; }
public double Dmg { get; set; }
}
class Program
{
static void Main(string[] args)
{
List<Thing> list=new List<Thing>() {
new Thing() { Name = "wq", TheOne = 1.1, Dmg=120 },
new Thing() { Name = "r", TheOne = 0.2, Dmg=60 },
new Thing() { Name = "e", TheOne = 0.8, Dmg=50 },
new Thing() { Name = "ba", TheOne = 1.2, Dmg=40 },
new Thing() { Name = "extra", TheOne = 0.8, Dmg=500 },
};
list.Sort((t1, t2) => t1.TheOne.CompareTo(t2.TheOne));
double[] dmg_list=list.Select((t) => t.Dmg).ToArray();
}
}
Edit 1
A constructor to Thing can be used to assign values with one operation.
public class Thing
{
// Constructor sets all the values
public Thing(string name, double theone, double dmg)
{
this.Name=name;
this.TheOne=theone;
this.Dmg=dmg;
}
public string Name { get; private set; }
public double TheOne { get; private set; }
public double Dmg { get; private set; }
}
class Program
{
static void Main(string[] args)
{
List<Thing> list=new List<Thing>();
list.Add(new Thing("wq", 1.1, 120));
list.Add(new Thing("r", 0.2, 60));
list.Add(new Thing("e", 0.8, 50));
list.Add(new Thing("ba", 1.2, 40));
list.Add(new Thing("extra", 0.8, 500));
list.Sort((t1, t2) => t1.TheOne.CompareTo(t2.TheOne));
double[] dmg_list=list.Select((t) => t.Dmg).ToArray();
}
}
This is my input store in file:
50|Carbon|Mercury|P:4;P:00;P:1
90|Oxygen|Mars|P:10;P:4;P:00
90|Serium|Jupiter|P:4;P:16;P:10
85|Hydrogen|Saturn|P:00;P:10;P:4
Now i will take my first row P:4 and then next P:00 and then next like wise and want to count occurence in every other row so expected output will be:
P:4 3(found in 2nd row,3rd row,4th row(last cell))
P:00 2 (found on 2nd row,4th row)
P:1 0 (no occurences are there so)
P:10 1
P:16 0
etc.....
Like wise i would like to print occurence of each and every proportion.
So far i am successfull in splitting row by row and storing in my class file object like this:
public class Planets
{
//My rest fields
public string ProportionConcat { get; set; }
public List<proportion> proportion { get; set; }
}
public class proportion
{
public int Number { get; set; }
}
I have already filled my planet object like below and Finally my List of planet object data is like this:
List<Planets> Planets = new List<Planets>();
Planets[0]:
{
Number:50
name: Carbon
object:Mercury
ProportionConcat:P:4;P:00;P:1
proportion[0]:
{
Number:4
},
proportion[1]:
{
Number:00
},
proportion[2]:
{
Number:1
}
}
Etc...
I know i can loop through and perform search and count but then 2 to 3 loops will be required and code will be little messy so i want some better code to perform this.
Now how do i search each and count every other proportion in my planet List object??
Well, if you have parsed proportions, you can create new struct for output data:
// Class to storage result
public class Values
{
public int Count; // count of proportion entry.
public readonly HashSet<int> Rows = new HashSet<int>(); //list with rows numbers.
/// <summary> Add new proportion</summary>
/// <param name="rowNumber">Number of row, where proportion entries</param>
public void Increment(int rowNumber)
{
++Count; // increase count of proportions entries
Rows.Add(rowNumber); // add number of row, where proportion entry
}
}
And use this code to fill it. I'm not sure it's "messy" and don't see necessity to complicate the code with LINQ. What do you think about it?
var result = new Dictionary<int, Values>(); // create dictionary, where we will storage our results. keys is proportion. values - information about how often this proportion entries and rows, where this proportion entry
for (var i = 0; i < Planets.Count; i++) // we use for instead of foreach for finding row number. i == row number
{
var planet = Planets[i];
foreach (var proportion in planet.proportion)
{
if (!result.ContainsKey(proportion.Number)) // if our result dictionary doesn't contain proportion
result.Add(proportion.Number, new Values()); // we add it to dictionary and initialize our result class for this proportion
result[proportion.Number].Increment(i); // increment count of entries and add row number
}
}
You can use var count = Regex.Matches(lineString, input).Count;. Try this example
var list = new List<string>
{
"50|Carbon|Mercury|P:4;P:00;P:1",
"90|Oxygen|Mars|P:10;P:4;P:00",
"90|Serium|Jupiter|P:4;P:16;P:10",
"85|Hydrogen|Saturn|P:00;P:10;P:4"
};
int totalCount;
var result = CountWords(list, "P:4", out totalCount);
Console.WriteLine("Total Found: {0}", totalCount);
foreach (var foundWords in result)
{
Console.WriteLine(foundWords);
}
public class FoundWords
{
public string LineNumber { get; set; }
public int Found { get; set; }
}
private List<FoundWords> CountWords(List<string> words, string input, out int total)
{
total = 0;
int[] index = {0};
var result = new List<FoundWords>();
foreach (var f in words.Select(word => new FoundWords {Found = Regex.Matches(word, input).Count, LineNumber = "Line Number: " + index[0] + 1}))
{
result.Add(f);
total += f.Found;
index[0]++;
}
return result;
}
I made a DotNetFiddle for you here: https://dotnetfiddle.net/z9QwmD
string raw =
#"50|Carbon|Mercury|P:4;P:00;P:1
90|Oxygen|Mars|P:10;P:4;P:00
90|Serium|Jupiter|P:4;P:16;P:10
85|Hydrogen|Saturn|P:00;P:10;P:4";
string[] splits = raw.Split(
new string[] { "|", ";", "\n" },
StringSplitOptions.None
);
foreach (string p in splits.Where(s => s.ToUpper().StartsWith(("P:"))).Distinct())
{
Console.WriteLine(
string.Format("{0} - {1}",
p,
splits.Count(s => s.ToUpper() == p.ToUpper())
)
);
}
Basically, you can use .Split to split on multiple delimiters at once, it's pretty straightforward. After that, everything is gravy :).
Obviously my code simply outputs the results to the console, but that part is fairly easy to change. Let me know if there's anything you didn't understand.