Develop Reference

How to swap huge string

I have huge string e.g (This is just the part, the string looks same it has just a bit different values).
string numbers = "48.7465504247904 9.16364437205161 48.7465666577545 9.16367275419435 48.746927738083 9.16430761814855 48.7471066512883 9.16462219521963 48.7471147950429";
So I have to swap the whole number e.g.
Output should be:
9.16364437205161 48.7465504247904
Also I need to swap the first and second part.
So I've tried to split the string, and then to replace the old one with the new one.
string numbers = "48.7465504247904 9.16364437205161 48.7465666577545 9.16367275419435 48.746927738083 9.16430761814855 48.7471066512883 9.16462219521963 48.7471147950429";
string output = "";
double first = 0;
double second = 0;
for (int i = 0; i < numbers.Length; i++)
{
numbers.Split(' ');
first = numbers[0];
second = numbers[1];
}
output = numbers.Replace(numbers[1], numbers[0]);
Console.WriteLine(output);
But my variable first always after the loop has the value 52.
Right now my output is: 44.7465504247904 9.16364437205161, it changed the first part, also it calculates somehow -4
.

You're not assigning anything to the value coming back from .Split and, if I read this right, you're also iterating each character in the numbers array for unclear reasons.
Using .Split is all you need ... well, and System.Linq
using System.Linq;
// ...
string SwapNumbers(string numbers) {
return numbers.Split(' ').Reverse().Join();
}
The above assumes you want to reverse the whole series of numbers. It absolutely does not swap 1,2 then swap 3,4 etc. If that's what you're looking for, it's a bit more involved and I'll add that in a second for funsies.
string SwapAlternateNumbers(string numbersInput) {
var wholeSeries = numbersInput.Split(' ').ToList();
// odd number of inputs
if (wholeSeries.Count % 2 != 0) {
throw new InvalidOperationException("I'm not handling this use case for you.");
}
var result = new StringBuilder();
for(var i = 0; i < wholeSeries.Count - 1; i += 2) {
// append the _second_ number
result.Append(wholeSeries[i+1]).Append(" ");
// append the _first_ number
result.Append(wholeSeries[i]).Append(" ");
}
// assuming you want the whole thing as a string
return result.ToString();
}
Edit: converted back to input and output string. Sorry about the enumerables; that's a difficult habit to break.

here
public static void Main()
{
string nums = "48.7465504247904 9.16364437205161 48.7465504247904 9.16364437205161";
var numbers = nums.Split(' ');
var swapped = numbers.Reverse();
Console.WriteLine("Hello World {"+string.Join(" ",swapped.ToArray())+"}");
}

Find index locations of a specified letter in a string

My apologies if I didn't explain it clear the first time. I have edited my explanation further in bold below.
In the program below user enters a word and then enters a letter which the user would like to replace with any character. For instance, user enter's a word "Hello" and the replacement letter is "l" with "$". So "Hello" will become "He$$o". First, the goal is to find the location of "l" (example - 2,3) and then replace the element in that specific location.
I started by finding the location of "l" and storing it in a findIndex array. Every time I run the program I get "22222" stored in findIndex[] array. At this point, I am not even sure if I am even applying the right logic. Any advice will be appreciated! Please don't use LINQ.
public static void RemoveSpecifiedCharacters()
{
Console.WriteLine("\nWrite a word/sentence: ");
string myString = Console.ReadLine();
Console.Write("Type the character you would like to replace: ");
string myCharacter = Console.ReadLine();
int[] findIndex = new int[myString.Length];
for (int i = 0; i < myString.Length; i++)
{
findIndex[i] = myString.IndexOf(myCharacter, 0);
}
for (int i = 0; i < findIndex.Length; i++)
{
Console.Write(findIndex[i]);
}
}

This is probably what you want :
public static void RemoveSpecifiedCharacters()
{
Console.WriteLine("\nWrite a word/sentence: ");
string myString = Console.ReadLine();
Console.Write("Type the character you would like to replace: ");
string myCharacter = Console.ReadLine();
List<int> findIndex = new List<int>();
int offs = 0;
while (offs < myString.Length)
{
offs = myString.IndexOf(myCharacter, offs);;
if (offs == -1)
break;
findIndex.Add(offs);
offs++;
}
for (int i = 0; i < findIndex.Count; i++)
{
Console.Write(findIndex[i]);
}
}
Set an initial offset to the start of the string, try to find index of required character if not found exit, otherwise store the location & increment the offset so the next loop starts after the found position. Then keep looping.
As you do not know how many characters will be found, then a list is better than an array to store the results. It can always be converted to an array with .ToArray() afterwards.

Below should serve the purpose :
var str = "Hello";
var replaced = str.Replace('l', '$');

Even though it's easier to use String.Replace, I just want to give you an explanation why you are getting [2,2,2,2,2] array.
Firstly, IndexOf method returns index of character's first occurence, starting from 0.
Secondly, you are using method overload IndexOf(myCharacter, 0) which "says" that character search should be done always from the start of the string.
To circumvent the issue, you should use IndexOf(myCharacter, i, 1) instead to set the search to start from i-th character, not the start of string.

I guess a simple solution would be to split the string into a character array and then do the comparison?
For example something like:
Console.WriteLine("\nWrite a word/sentence: ");
char[] myString = Console.ReadLine().ToCharArray();
Console.Write("Type the character you would like to replace: ");
char myCharacter = Console.ReadLine().ToCharArray()[0];
int[] findIndex = new int[myString.Length];
int indexCount = 0;
for (int i = 0; i < myString.Length; i++)
{
if (myString[i] == myCharacter)
findIndex[indexCount++] = i;
}
for (int i = 0; i < indexCount; i++)
{
Console.Write(findIndex[i]);
}

count the number of points at the end of a string

I need to count the number of points at the END of string.
The number of points in the middle of the string are not relevant and should not be countet.
How can this be done?
string sample = "This.is.a.sample.string.....";
for the example above the correct answer would be 5 because there are 5 points at the end of the string.
because of performace reasons I would prefer a fast solution. Don't know if Regular Expressions
\.*$
should be used in such a case.

Start from the end of the string and go back char by char until its not a dot:
string sample = "This.is.a.sample.string....."
int count = 0;
for (int i = sample.Length - 1; i >= 0; i--)
{
if (sample[i] != '.') break;
count++;
}

Using Linq:
var test = "this.is.a.test........";
var count = test.ToCharArray().Reverse().TakeWhile(q => q == '.').Count();
Convert string to array, reverse, then take while character = '.'. Count result.

A simple solution using an extension method.
var test = "this.is.a.test........";
Console.WriteLine(test.CountTrailingDots());
public static int CountTrailingDots(this string value)
{
return value.Length - value.TrimEnd('.').Length;
}

Using Regex:
int points = Regex.Match("This.is.a.sample.string....", #"^[\w\W]*?([.]*+)$").Groups[1].Value.Length;
Description:
*+ = Matches as many characters as possible
*? = Matches as few characters as possible.

It can be something like..
string sample = "This.is.a.sample.string.....";
int count = 0;
if(sample.EndsWith("."))
count = sample.Substring(sample.TrimEnd('.').Length).Length;

Char/String comparison

I'm trying to have a suggestion feature for the search function in my program eg I type janw doe in the search section and it will output NO MATCH - did you mean jane doe? I'm not sure what the problem is, maybe something to do with char/string comparison..I've tried comparing both variables as type char eg char temp -->temp.Contains ...etc but an error appears (char does not contain a definition for Contains). Would love any help on this! 8)
if (found == false)
{
Console.WriteLine("\n\nMATCH NOT FOUND");
int charMatch = 0, charCount = 0;
string[] checkArray = new string[26];
//construction site /////////////////////////////////////////////////////////////////////////////////////////////////////////////
for (int controlLoop = 0; controlLoop < contPeople.Length; controlLoop++)
{
foreach (char i in userContChange)
{
charCount = charCount + 1;
}
for (int i = 0; i < userContChange.Length; )
{
string temp = contPeople[controlLoop].name;
string check=Convert.ToString(userContChange[i]);
if (temp.Contains(check))
{
charMatch = charMatch + 1;
}
}
int half = charCount / 2;
if (charMatch >= half)
{
checkArray[controlLoop] = contPeople[controlLoop].name;
}
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////
Console.WriteLine("Did you mean: ");
for (int a = 0; a < checkArray.Length; a++)
{
Console.WriteLine(checkArray[a]);
}
///////////////////////////////////////////////////////////////////////////////////////////////////

A string is made up of many characters. A character is a primitive, likewise, it doesn't "contain" any other items. A string is basically an array of characters.
For comparing string and characters:
char a = 'A';
String alan = "Alan";
Debug.Assert(alan[0] == a);
Or if you have a single digit string.. I suppose
char a = 'A';
String alan = "A";
Debug.Assert(alan == a.ToString());
All of these asserts are true
But, the main reason I wanted to comment on your question, is to suggest an alternative approach for suggesting "Did you mean?". There's an algorithm called Levenshtein Distance which calculates the "number of single character edits" required to convert one string to another. It can be used as a measure of how close two strings are. You may want to look into how this algorithm works because it could help you.
Here's an applet that I found which demonstrates: Approximate String Matching with k-differences
Also the wikipedia link Levenshtein distance

Char type cannot have .Contains() because is only 1 char value type.
In your case (if i understand), maybe you need to use .Equals() or the == operator.
Note: for compare String correctly, use .Equals(),
the == operator does not work good in this case because String is reference type.
Hope this help!

char type dosen't have the Contains() method, but you can use iit like this: 'a'.ToString().Contains(...)
if do not consider the performance, another simple way:
var input = "janw doe";
var people = new string[] { "abc", "123", "jane", "jane doe" };
var found = Array.BinarySearch<string>(people, input);//or use FirstOrDefault(), FindIndex, search engine...
if (found < 0)//not found
{
var i = input.ToArray();
var target = "";
//most similar
//target = people.OrderByDescending(p => p.ToArray().Intersect(i).Count()).FirstOrDefault();
//as you code:
foreach (var p in people)
{
var count = p.ToArray().Intersect(i).Count();
if (count > input.Length / 2)
{
target = p;
break;
}
}
if (!string.IsNullOrWhiteSpace(target))
{
Console.WriteLine(target);
}
}

Regex to find first capital letter occurrence in a string

I want to find the index of first capital letter occurrence in a string.
E.g. -
String x = "soHaM";
Index should return 2 for this string. The regex should ignore all other capital letters after the first one is found. If there are no capital letters found then it should return 0. Please help.

I'm pretty sure all you need is the regex A-Z \p{Lu}:
public static class Find
{
// Apparently the regex below works for non-ASCII uppercase
// characters (so, better than A-Z).
static readonly Regex CapitalLetter = new Regex(#"\p{Lu}");
public static int FirstCapitalLetter(string input)
{
Match match = CapitalLetter.Match(input);
// I would go with -1 here, personally.
return match.Success ? match.Index : 0;
}
}
Did you try this?

Just for fun, a LINQ solution:
string x = "soHaM";
var index = from ch in x.ToArray()
where Char.IsUpper(ch)
select x.IndexOf(ch);
This returns IEnumerable<Int32>. If you want the index of the first upper case character, simply call index.First() or retrieve only the first instance in the LINQ:
string x = "soHaM";
var index = (from ch in x.ToArray()
where Char.IsUpper(ch)
select x.IndexOf(ch)).First();
EDIT
As suggested in the comments, here is another LINQ method (possibly more performant than my initial suggestion):
string x = "soHaM";
x.Select((c, index) => new { Char = c, Index = index }).First(c => Char.IsUpper(c.Char)).Index;

No need for Regex:
int firstUpper = -1;
for(int i = 0; i < x.Length; i++)
{
if(Char.IsUpper(x[i]))
{
firstUpper = i;
break;
}
}
http://msdn.microsoft.com/en-us/library/system.char.isupper.aspx
For the sake of completeness, here's my LINQ approach(although it's not the right tool here even if OP could use it):
int firstUpperCharIndex = -1;
var upperChars = x.Select((c, index) => new { Char = c, Index = index })
.Where(c => Char.IsUpper(c.Char));
if(upperChars.Any())
firstUpperCharIndex = upperChars.First().Index;

First your logic fails, if the method returns 0 in your case it would mean the first char in that list was in upperCase, so I would recomend that -1 meens not found, or throw a exception.
Anyway just use regular expressions becasue you can is not always the best choise, plus they are pretty slow and hard to read in general, making yoru code much harder to work with.
Anyway here is my contribution
public static int FindFirstUpper(string text)
{
for (int i = 0; i < text.Length; i++)
if (Char.IsUpper(text[i]))
return i;
return -1;
}

Using Linq:
using System.Linq;
string word = "soHaMH";
var capChars = word.Where(c => char.IsUpper(c)).Select(c => c);
char capChar = capChars.FirstOrDefault();
int index = word.IndexOf(capChar);
Using C#:
using System.Text.RegularExpressions;
string word = "soHaMH";
Match match= Regex.Match(word, "[A-Z]");
index = word.IndexOf(match.ToString());

Using loop
int i = 0;
for(i = 0; i < mystring.Length; i++)
{
if(Char.IsUpper(mystring, i))
break;
}
i is the value u should be looking at;