Develop Reference

How can I split a string like "12-15" into two numbers?

My front-end application sends strings that look like this:
"12-15"
to a back-end C# application.
Can someone give me some pointers as to how I could extract the two numbers into two variables. Note the format is always the same with two numbers and a hyphen between them.

string stringToSplit = "12-15";
string[] splitStringArray;
splitStringArray = stringToSplit.Split('-');
splitStringArray[0] will be 12
splitStringArray[1] will be 15

Split the string into parts:
string s = "12-15";
string[] num = s.Split('-');
int part1 = Convert.ToInt32(num[0]);
int part2 = Convert.ToInt32(num[1]);

int[] numbers = "12-15".Split('-')
.Select(x => {
int n;
int.TryParse(x, out n);
return n;
})
.ToArray();

We call Split on a string instance. This program splits on a single character
string s ="12-15";
string[] words = s.Split('-');
foreach (string word in words)
{
int convertedvalue = Convert.ToInt32(word );
Console.WriteLine(word);
}
string[] ss= s.Split('-');
int x = Convert.ToInt32(ss[0]);
int y = Convert.ToInt32(ss[1]);
more info

You can use the below code to split and it will return string for each value, then you can typecast it to any type you wish to ...
string myString = "12-15-18-20-25-60";
string[] splittedStrings = myString.Split('-');
foreach (var splittedString in splittedStrings)
{
Console.WriteLine(splittedString + "\n");
}
Console.ReadLine();

Here is the correct version without the wrong code
string textReceived = "12-15";
string[] numbers = textReceived.Split('-');
List<int> numberCollection = new List<int>();
foreach (var item in numbers)
{
numberCollection.Add(Convert.ToInt32(item));
}

String numberString = "12-15" ;
string[] arr = numberString.Split("-");
Now you will get a string array , you can use parsing to get the numbers alone
int firstNumber = Convert.ToInt32(arr[0]);
Helpful answer related to parsing :
https://stackoverflow.com/a/199484/5395773

You could convert that string explicitly to an integer array using Array.ConvertAll method and access the numbers using their index, you can run the below example here.
using System;
namespace Rextester
{
public class Program
{
public static void Main(string[] args)
{
var number = "12-15";
var numbers = Array.ConvertAll(number.Split('-'), int.Parse);
Console.WriteLine(numbers[0]);
Console.WriteLine(numbers[1]);
}
}
}
Or you can explicitly convert the numeric string using int.Parse method, the int keyword is an alias name for System.Int32 and it is preffered over the complete system type name System.Int32, you can run the below example here.
using System;
namespace Rextester
{
public class Program
{
public static void Main(string[] args)
{
var number = "12-15";
var numbers = number.Split('-');
var one = int.Parse(numbers[0]);
var two = int.Parse(numbers[1]);
Console.WriteLine(one);
Console.WriteLine(two);
}
}
}
Additional read: Please check int.Parse vs. Convert.Int32 vs. int.TryParse for more insight on parsing the input to integer

string str = null;
string[] strArr = null;
int count = 0;
str = "12-15";
char[] splitchar = { '-' };
strArr = str.Split(splitchar);
for (count = 0; count <= strArr.Length - 1; count++)
{
MessageBox.Show(strArr[count]);
}

sub-strings replacements according to some mapping

Given a string, I need to replace substrings according to a given mapping. The mapping determines where to start the replacement, the length of text to be replaced and the replacement string. The mapping is according to the following scheme:
public struct mapItem
{
public int offset;
public int length;
public string newString;
}
For example: given a mapping {{0,3,"frog"},{9,3,"kva"}} and a string
"dog says gav"
we replace starting at position 0 a substring of the length 3 to the "frog", i.e.
dog - > frog
and starting the position 9 a substring of the length 3 to the "kva", i.e.
gav->kva
The new string becomes:
"frog says kva"
How can I do it efficiently?

You have to take care that replacements take into account the shift produced by preceding replacements. Also using a StringBuilder is more efficient, as is doesn't allocate new memory at each operation as string operations do. (Strings are invariant, which means that a completely new string is created at each string operation.)
var maps = new List<MapItem> { ... };
var sb = new StringBuilder("dog says gav");
int shift = 0;
foreach (MapItem map in maps.OrderBy(m => m.Offset)) {
sb.Remove(map.Offset + shift, map.Length);
sb.Insert(map.Offset + shift, map.NewString);
shift += map.NewString.Length - map.Length;
}
string result = sb.ToString();
The OrderBy makes sure that the replacements are executed from left to right. If you know that the mappings are provided in this order, you can drop the OrderBy.
Another simpler way is to begin with the replacements at the right end and work backwards, so that the character shifts do not alter the positions of not yet executed replacements:
var sb = new StringBuilder("dog says gav");
foreach (MapItem map in maps.OrderByDescending(m => m.Offset)) {
sb.Remove(map.Offset, map.Length);
sb.Insert(map.Offset, map.NewString);
}
string result = sb.ToString();
In case the mappings are already ordered in ascending order, a simple reverse for-statement seems appropriate:
var sb = new StringBuilder("dog says gav");
for (int i = maps.Count - 1; i >= 0; i--) {
MapItem map = maps[i];
sb.Remove(map.Offset, map.Length);
sb.Insert(map.Offset, map.NewString);
}
string result = sb.ToString();

You can write an Extension Method like below:
public static class ExtensionMethod
{
public static string ReplaceSubstringByMap(this string str, List<mapItem> map)
{
int offsetShift = 0;
foreach (mapItem mapItem in map.OrderBy(x => x.offset))
{
str = str.Remove(mapItem.offset + offsetShift, mapItem.length).Insert(mapItem.offset + offsetShift, mapItem.newString);
offsetShift += mapItem.newString.Length - mapItem.length;
}
return str;
}
}
And invoke it like below:
var map = new List<mapItem>
{
new mapItem
{
offset = 0,
length = 1,
newString = "frog"
},
new mapItem
{
offset = 9,
length = 1,
newString = "kva"
}
};
string str = "dog says gav";
var result = str.ReplaceSubstringByMap(map);

CUDA .Net compare strings

I'm trying to compare lists of strings (huge amount of elements in each of lists). Could somebody help me to do it using cudafy? I guess that in that case I should use jagged arrays of char but I've got an CudafyCompileException - expression must have class type (tried this approach). It worked just for two strings (char[]). So any ideas how I can do that?
Code sample for 2 strings:
var km = CudafyTranslator.Cudafy();
_gpu = CudafyHost.GetDevice();
_gpu.LoadModule(km);
var strFirst = "Hello, world";
var strSecond = "Hi world";
var devResult = _gpu.Allocate<char>(strFirst.Length);
var first = strFirst.ToCharArray();
var second = strSecond.ToCharArray();
var result = new char[strFirst.Length];
var devFirst = _gpu.CopyToDevice(first);
var devSecond = _gpu.CopyToDevice(second);
_gpu.Launch(N, 1).CompareStrings(devFirst, devSecond, devResult);
_gpu.CopyFromDevice(devResult, result);
var hostStr = new string(result);
Console.WriteLine(hostStr);
And the method itself:
[Cudafy]
public static void CompareStrings(GThread thread, char[] c, char[] b, char[] result)
{
int tid = thread.blockIdx.x;
if (tid < c.Length)
{
if (c[tid] == b[tid])
{
result[tid] = c[tid];
}
}
}

instead c.Length pass the length as a parameter
be careful if you useing Unicode character, that 2 bytes

Random string with no duplicates

I'm trying to generate a 16 chars random string with NO DUPLICATE CHARS. I thoght that it shouldn't be to hard but I'm stuck.
I'm using 2 methods, one to generate key and another to remove duplicate chars. In main I've created a while loop to make sure that generated string is 16 chars long.
There is something wrong with my logic because it just shoots up 16-char string
with duplicates. Just can't get it right.
The code:
public string RemoveDuplicates(string s)
{
string newString = string.Empty;
List<char> found = new List<char>();
foreach (char c in s)
{
if (found.Contains(c))
continue;
newString += c.ToString();
found.Add(c);
}
return newString;
}
public static string GetUniqueKey(int maxSize)
{
char[] chars = new char[62];
chars =
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890".ToCharArray();
byte[] data = new byte[1];
RNGCryptoServiceProvider crypto = new RNGCryptoServiceProvider();
crypto.GetNonZeroBytes(data);
data = new byte[maxSize];
crypto.GetNonZeroBytes(data);
StringBuilder result = new StringBuilder(maxSize);
foreach (byte b in data)
{
result.Append(chars[b % (chars.Length)]);
}
return result.ToString();
}
string builder = "";
do
{
builder = GetUniqueKey(16);
RemoveDuplicates(builder);
lblDir.Text = builder;
Application.DoEvents();
} while (builder.Length != 16);

Consider implementing shuffle algorithm with which you will shuffle your string with unique characters and then just pick up first 16 characters.
You can do this in-place, by allocating single StringBuffer which will contain your initial data ("abc....") and just use Durstenfeld's version of the algorithm to mutate your buffer, than return first 16 chars.

There are many algorithms for this.
One easy one is:
Fill an array of chars with the available chars.
Shuffle the array.
Take the first N items (where N is the number of characters you need).
Sample code:
using System;
namespace ConsoleApplication2
{
internal class Program
{
private static void Main(string[] args)
{
var chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890".ToCharArray();
Random rng = new Random();
for (int i = 0; i < 10; ++i)
{
string randomString = RandomString(16, chars, rng);
Console.WriteLine(randomString);
}
}
public static string RandomString(int n, char[] chars, Random rng)
{
Shuffle(chars, rng);
return new string(chars, 0, n);
}
public static void Shuffle(char[] array, Random rng)
{
for (int n = array.Length; n > 1; )
{
int k = rng.Next(n);
--n;
char temp = array[n];
array[n] = array[k];
array[k] = temp;
}
}
}
}

const string chars =
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
var r = new Random();
var s = new string(chars.OrderBy(x => r.Next()).Take(16).ToArray());

I am using a GUID generation method it itself generates random strings and you can modify it if a number appears in the beginning,
use the code given below:
string guid = System.Guid.NewGuid().ToString("N");
while (char.IsDigit(guid[0]))
guid = System.Guid.NewGuid().ToString("N");
Hope that helps.

See if this helps:
RandomString()
{
string randomStr = Guid.NewGuid().ToString();
randomStr = randomStr.Replace("-", "").Substring(0, 16);
Console.WriteLine(randomStr);
}
This returns alpha-numeric string.

Convert int to string?

How can I convert an int datatype into a string datatype in C#?

string myString = myInt.ToString();

string a = i.ToString();
string b = Convert.ToString(i);
string c = string.Format("{0}", i);
string d = $"{i}";
string e = "" + i;
string f = string.Empty + i;
string g = new StringBuilder().Append(i).ToString();

Just in case you want the binary representation and you're still drunk from last night's party:
private static string ByteToString(int value)
{
StringBuilder builder = new StringBuilder(sizeof(byte) * 8);
BitArray[] bitArrays = BitConverter.GetBytes(value).Reverse().Select(b => new BitArray(new []{b})).ToArray();
foreach (bool bit in bitArrays.SelectMany(bitArray => bitArray.Cast<bool>().Reverse()))
{
builder.Append(bit ? '1' : '0');
}
return builder.ToString();
}
Note: Something about not handling endianness very nicely...
If you don't mind sacrificing a bit of memory for speed, you can use below to generate an array with pre-calculated string values:
static void OutputIntegerStringRepresentations()
{
Console.WriteLine("private static string[] integerAsDecimal = new [] {");
for (int i = int.MinValue; i < int.MaxValue; i++)
{
Console.WriteLine("\t\"{0}\",", i);
}
Console.WriteLine("\t\"{0}\"", int.MaxValue);
Console.WriteLine("}");
}

int num = 10;
string str = Convert.ToString(num);

The ToString method of any object is supposed to return a string representation of that object.
int var1 = 2;
string var2 = var1.ToString();

Further on to #Xavier's response, here's a page that does speed comparisons between several different ways to do the conversion from 100 iterations up to 21,474,836 iterations.
It seems pretty much a tie between:
int someInt = 0;
someInt.ToString(); //this was fastest half the time
//and
Convert.ToString(someInt); //this was the fastest the other half the time

string str = intVar.ToString();
In some conditions, you do not have to use ToString()
string str = "hi " + intVar;

or:
string s = Convert.ToString(num);

using System.ComponentModel;
TypeConverter converter = TypeDescriptor.GetConverter(typeof(int));
string s = (string)converter.ConvertTo(i, typeof(string));

None of the answers mentioned that the ToString() method can be applied to integer expressions
Debug.Assert((1000*1000).ToString()=="1000000");
even to integer literals
Debug.Assert(256.ToString("X")=="100");
Although integer literals like this are often considered to be bad coding style (magic numbers) there may be cases where this feature is useful...

string s = "" + 2;
and you can do nice things like:
string s = 2 + 2 + "you"
The result will be:
"4 you"

if you're getting from a dataset
string newbranchcode = (Convert.ToInt32(ds.Tables[0].Rows[0]["MAX(BRANCH_CODE)"]) ).ToString();