I was just wondering if there is a simple way of doing this. i.e. Replacing the occurrence of consecutive characters with the same character.
For eg: - if my string is "something likeeeee tttthhiiissss" then my final output should be "something like this".
The string can contain special characters too including space.
Can you guys suggest some simple way for doing this.
This should do it:
var regex = new Regex("(.)\\1+");
var str = "something likeeeee!! tttthhiiissss";
Console.WriteLine(regex.Replace(str, "$1")); // something like! this
The regex will match any character (.) and \\1+ will match whatever was captured in the first group.
string myString = "something likeeeee tttthhiiissss";
char prevChar = '';
StringBuilder sb = new StringBuilder();
foreach (char chr in myString)
{
if (chr != prevChar) {
sb.Append(chr);
prevChar = chr;
}
}
How about:
s = new string(s
.Select((x, i) => new { x, i })
.Where(x => x.i == s.Length - 1 || s[x.i + 1] != x.x)
.Select(x => x.x)
.ToArray());
In english, we are creating a new string based on a char[] array. We construct that char[] array by applying a few LINQ operators:
Select: Capture the index i along with the current character x.
Filter out charaters that are not the same as the subsequent character
Select the character x.x back out of the anonymous type x.
Convert back to a char[] array so we can pass to constructor of string.
Console.WriteLine("Enter any string");
string str1, result="", str = Console.ReadLine();
char [] array= str.ToCharArray();
int i=0;
for (i = 0; i < str.Length;i++ )
{
if ((i != (str.Length - 1)))
{ if (array[i] == array[i + 1])
{
str1 = str.Trim(array[i]);
}
else
{
result += array[i];
}
}
else
{
result += array[i];
}
}
Console.WriteLine(result);
In this code the program ;
will read the string as entered from user
2.Convert the string in char Array using string.ToChar()
The loop will run for each character in string
each character stored in that particular position in array will be compared to the character stored in position one greater than that . And if the characters are found same the character stored in that particular array would be trimmed using .ToTrim()
For last character the loop will show error of index out of bound as it would be the last position value of the array. That's why I used * if ((i != (str.Length - 1)))*
6.The characters left after trimming are stored in result in concatenated form .
word = "something likeeeee tttthhiiissss"
re.sub(r"(.)\1+", r"\1",word)
Related
I want to replace a string (that the user inputs) with the next character in the alphabet. I'm having trouble returning the next value from my loop.
Error message: Index was outside the bounds of the array.
I understand that the array ends, and that might be a problem from the +1 I entered. How would I go about solving this?
string inputString = "abcdefghijklmnopqqrstuvxyz";
char[] inputCharArray = inputString.ToCharArray();
char[] alphabetArray = "abcdefghijklmnopqrstuvxyz".ToArray();
var resultStr = "";
for (int i = 0; i < inputCharArray.Length; i++)
{
if(alphabetArray.Contains(inputCharArray[i]))
resultStr += inputCharArray[i+1];
else
resultStr += inputCharArray[i];
}
System.Console.WriteLine(resultStr);
You're getting an Out Of Range exception because i will eventually equal the last index of your input array, and adding 1 to that number is beyond what the array has.
First, make it easier on yourself by making a function to convert a single char into the next letter.
Note, this answer assumes that you want to "wrap around" - the next letter after "z" goes back to "a".
char NextLetter(char input)
{
if (input < 'a' || input > 'z') // simple validation
throw new ArgumentException();
input += (char)1; // go to the next char value
if (input > 'z') // did you go past z?
input = 'a'; // go back to a
return input;
}
Yes, you can also do modulo, this method is the simple version.
Now you can loop through all the letters in your input to construct the output string. In addition, you don't need to .ToCharArray() a string - a string already implements IEnumerable<char>.
var input = "abcxyz";
var outputBuilder = new StringBuilder();
foreach (char letter in input)
{
outputBuilder.Append(NextLetter(letter));
}
Console.WriteLine(outputBuilder.ToString());
// prints "bcdyza"
You can use Array.IndexOf to find the index of the current character in the alphabet, then you can use the modulo operator (%) to get the index of the next character in the alphabet (assuming the alphabet wraps from z to a in your desired solution):
string inputString = "abcdefghijklmnopqqrstuvxyz";
char[] inputCharArray = inputString.ToCharArray();
char[] alphabetArray = "abcdefghijklmnopqrstuvxyz".ToArray();
var resultStr = "";
for (var i = 0; i < inputCharArray.Length; i++)
{
var indexInAlphabet = Array.IndexOf(alphabetArray, inputCharArray[i]);
var indexOfNextLetter = (indexInAlphabet + 1) % alphabetArray.Length;
resultStr += alphabetArray[indexOfNextLetter];
}
Console.WriteLine(resultStr);
Create an application with a method that accepts a string as an argument and returns a copy of the string with the first character of each sentence capitalized.
This is what I have to far and I can't seem to get it right:
//Create method to process string.
private string Sentences(string input)
{
//Capitalize first letter of input.
char firstLetter = char.ToUpper(input[0]);
//Combine the capitalize letter with the rest of the input.
input = firstLetter.ToString() + input.Substring(1);
//Create a char array to hold all characters in input.
char[] letters = new char[input.Length];
//Read the characters from input into the array.
for (int i = 0; i < input.Length; i++)
{
letters[i] = input[i];
}
//Loop through array to test for punctuation and capitalize a character 2 index away.
for (int index = 0; index < letters.Length; index++)
{
if(char.IsPunctuation(letters[index]))
{
if (!((index + 2) >= letters.Length))
{
char.ToUpper(letters[index+ 2]);
}
}
}
for(int ind = 0; ind < letters.Length; ind++)
{
input += letters[ind].ToString();
}
return input;
}
You could use Linq.Aggregate n - see comments in code and code output for explanation how it work's.
This one will respect "Bla. blubb" as well - you need to check for whitespaces after ".?!"
using System;
using System.Linq;
internal class Program
{
static string Capitalize(string oldSentence )
{
return
// this will look at oldSentence char for char, we start with a
// new string "" (the accumulator, short acc)
// and inspect each char c of oldSentence
// comment all the Console.Writelines in this function, thats
// just so you see whats done by Aggregate, not needed for it to
// work
oldSentence
.Aggregate("", (acc, c) =>
{
System.Console.WriteLine("Accumulated: " + acc);
System.Console.WriteLine("Cecking: " + c);
// if the accumulator is empty or the last character of
// trimmed acc is a ".?!" we append the
// upper case of c to it
if (acc.Length == 0 || ".?!".Any(p => p == acc.Trim().Last())) // (*)
acc += char.ToUpper(c);
else
acc += c; // else we add it unmodified
System.Console.WriteLine($"After: {acc}\n");
return acc; // this returns the acc for the next iteration/next c
});
}
static void Main(string[] args)
{
Console.SetBufferSize(120, 1000);
var oldSentence = "This is a testSentence. some occurences "
+ "need capitalization! for examlpe here. or here? maybe "
+ "yes, maybe not.";
var newSentence = Capitalize(oldSentence);
Console.WriteLine(new string('*', 80));
Console.WriteLine(newSentence);
Console.ReadLine();
}
}
(*)
".?!".Any(p => p == ... )) means does the string ".?!" contain any character that equals ...
acc.Trim().Last() means: remove whitespaces in front/on end of acc and give me the last character
.Last() and .Any() are also Linq. Most of the Linq-esc extension can be found here: https://msdn.microsoft.com/en-us/library/9eekhta0(v=vs.110).aspx
Output (snipped - its rather longish ;o)
Accumulated:
Cecking: T
After: T
Accumulated: T
Cecking: h
After: Th
Accumulated: Th
Cecking: i
After: Thi
Accumulated: Thi
Cecking: s
After: This
Accumulated: This
Cecking:
After: This
Accumulated: This
Cecking: i
After: This i
Accumulated: This i
Cecking: s
After: This is
<snipp - .. you get the idea how Aggregate works ...>
Accumulated: This is a testSentence.
Cecking: s
After: This is a testSentence. S
<snipp>
Accumulated: This is a testSentence. Some occurences need capitalization!
Cecking: f
After: This is a testSentence. Some occurences need capitalization! F
<snipp>
********************************************************************************
This is a testSentence. Some occurences need capitalization! For examlpe here. Or here? Maybe yes, maybe not.
I would suggest to use a regex to identify all the dots in your sentence. Get the match, make it upper case and replace it back in the original sentence, in the match index. I dont actually have any IDE in which try the code on .NET right now but i can write it in pseudocode for better understanding.
String setence = "your.setence.goes.here";
Regex rx = new Regex("/\..*?[A-Z]/");
foreach (Match match in rx.Matches(sentence))
{
setence.remove(match.Index, 2).insert(match.Index, String.ToUpper(match.Value));
}
You have two tasks:
1) Split text into sentences
2) Capitalize the first char in the sentences
Task one can be very complex, e.g. because there a lot of crazy languages out there. Put since this is homework I assume you can go ahead and simply split by well know separators.
Task two is just about basic string operations. You select the first char, make it uppercase and add the missing part of the sentence via a substring operation.
Here is a code example:
char[] separators = new char[] { '!', '.', '?' };
string[] sentencesArray = "First sentence. second sentence!lastone.".Split(separators, StringSplitOptions.RemoveEmptyEntries);
var i = 0;
Array.ForEach(sentencesArray, e =>
{
sentencesArray[i] = e.Trim().First().ToString().ToUpper() +
e.Trim().Substring(1);
i++;
});
I Have created a method in Groovy for the same
String capitalizeFirstCharInSentence(String str) {
String result = ''
str = str.toLowerCase()
List<String> strings = str.tokenize('.')
strings.each { line ->
StringBuilder builder = new StringBuilder(line)
int i = 0
while (i < builder.size() - 1 && !Character.isLowerCase(builder.charAt(i))) {
i++
}
if (Character.isLowerCase(builder.charAt(i))) {
builder.setCharAt(i, builder.charAt(i).toUpperCase())
result += builder.toString() + '.'
}
}
return result
}
I liked the way you formatted your method because it made it easy for newer coders to read so I decided to try to make the code work while maintaining the structure. The main problem I saw was that you were not replacing the arrays after formatting them.
//Create method to process string.
private string Sentences(string input)
{
//Create a char array to hold all characters in input.
char[] letters = new char[input.Length];
//Read the characters from input into the array.
for (int i = 0; i < input.Length; i++)
{
letters[i] = input[i];
}
//Capitalize first letter of input.
letters[0] = char.ToUpper(letters[0]);
//Loop through array to test for punctuation and capitalize a character 2 index away.
for (int index = 0; index < letters.Length; index++)
{
if(char.IsPunctuation(letters[index]))
{
if (index + 2 <= letters.Length)
{
letters[index + 2] = char.ToUpper(letters[index+ 2]);
}
}
}
// convert array back to string
string results = new string(letters)
return results;
}
Need some help finding specific letters in string.
I need to find letters "aeiou" in string array and in the output to get just position of that first found letter.
Everything in C#.
string array = "Elephants are dangerous";
string letters = "aeiou";
if (array.All(letters.Contains))
{
Console.WriteLine("Letter: {0}",letters);
}
where I made mistake?
int? minIndex =
letters
.Select(l => (int?)array.IndexOf(l))
.Where(idx => idx != -1)
.Min();
I'd prefer this over any kind of loop solution. This is concise, obviously correct and maintainable in the face of changing requirements.
string array = "Elephants are dangerous";
char[] letters = ("aeiou").ToCharArray(); // make char array to iterate through all characters. you could make this also "inline" in the foreach i just left it her so you see what's going on.
int firstIndex = int.MaxValue;
char firstletter = '?';
foreach (char letter in letters) // iterate through all charecters you're searching for
{
int index = array
.ToLower() // to lower -> remove this line if you want to have case sensitive search
.IndexOf(letter); // get the index of the current letter
//check if the character is found and if it's the earliest position
if (index != -1 && index < firstIndex )
{
firstIndex = index;
firstletter = letter;
}
}
Console.WriteLine("Letter: {0} # {1}", firstletter, firstIndex);
EDIT
if you prefer to go with LINQ:
NOTE: Please take a look at "usr" answer. It's much more cleaner ;-)
string array = "Elephants are dangerous";
char[] letters = ("aeiou").ToCharArray();
char firstletter = array.ToLower().First(c => letters.Contains(c));
int firstIndex = array.ToLower().IndexOf(firstletter);
Console.WriteLine("Letter: {0} # {1}", firstletter, firstIndex);
EDIT2 and here you go with a Regular Expression
string array = "Elephants are dangerous";
Match match = Regex.Match(array.ToLower(), "[aeiou]");
if (match.Success)
{
Console.WriteLine("Letter: {0} # {1}", match.Value, match.Index);
}
https://www.dotnetperls.com/regex
Everyone knows how to replace a character in a string with:
string text = "Hello World!";
text = text.Replace("H","J");
but what I need is to replace multiple characters in a string
something like:
string text = textBox1.Text;
text = text.Replace("a","b")
text = text.Replace("b","a")
now the result is aa , but if the user types ab I want the result to be ba
There's multiple ways to do this.
Using a loop
char[] temp = input.ToCharArray();
for (int index = 0; index < temp.Length; index++)
switch (temp[index])
{
case 'a':
temp[index] = 'b';
break;
case 'b':
temp[index] = 'a';
break;
}
string output = new string(temp);
This will simply copy the string to a character array, fix each character by itself, then convert the array back into a string. No risk of getting any of the characters confused with any of the others.
Using a regular expression
You can exploit this overload of Regex.Replace:
public static string Replace(
string input,
string pattern,
MatchEvaluator evaluator
)
This takes a delegate that will be called for each match, and return the final result. The delegate is responsible for returning what each match should be replaced with.
string output = Regex.Replace(input, ".", ma =>
{
if (ma.Value == "a")
return "b";
if (ma.Value == "b")
return "a";
return ma.Value;
});
For your particular requirement I would suggest you to use like the following:
string input = "abcba";
string outPut=String.Join("",input.ToCharArray()
.Select(x=> x=='a'? x='b':
(x=='b'?x='a':x))
.ToArray());
The output string will be bacab for this particular input
Do not call String.Replace multiple times for the same string! It creates a new string every time (also it has to cycle through the whole string every time) causing memory pressure and processor time waste if used a lot.
What you could do:
Create a new char array with the same length as the input string. Iterate over all chars of the input strings. For every char, check whether it should be replaced. If it should be replaced, write the replacement into the char array you created earlier, otherwise write the original char into that array. Then create a new string using that char array.
string inputString = "aabbccdd";
char[] chars = new char[inputString.Length];
for (int i = 0; i < inputString.Length; i++)
{
if (inputString[i] == 'a')
{
chars[i] = 'b';
}
else if (inputString[i] == 'b')
{
chars[i] = 'a';
}
else
{
chars[i] = inputString[i];
}
}
string outputString = new string(chars);
Consider using a switch when intending to replace a lot of different characters.
Use should use StringBuilder when you are concatenating many strings in a loop like this, so I suggest the following solution:
StringBuilder sb = new StringBuilder(text.Length);
foreach(char c in text)
{
sb.Append(c == 'a' ? 'b' : 'a');
}
var result = sb.ToString();
I need to alternate the case in a sentence and I don't know how to.
For example:
thequickbrownfoxjumpsoverthelazydog
to
GoDyZaLeHtReVoSpMuJxOfNwOrBkCiUqEhT
this is my code so far
Console.WriteLine("Please enter a sentence:");
string text = Console.ReadLine();
text = text.Replace(" ", "");
char[] reversed = text.ToCharArray();//String to char
Array.Reverse(reversed);//Reverses char
new string(reversed);//Char to string
Console.WriteLine(reversed);
Console.ReadLine();
Please note that there are no spaces for a reason as that's also part of the homework task.
A string is immutable, so, you need to convert it to a char[].
char[] characters = text.ToCharArray();
for (int i = 0; i < characters.Length; i+=2) {
characters[i] = char.ToUpper(characters[i]);
}
text = new string(characters);
There is no point to reverse your string. Just upper case your even number indexed characters in your string.
Remember, my culture is tr-TR and this String.ToUpper method works depends on your current thread culture. In this example, your output can be different than mine.
Here an example in LINQPad;
string s = "thequickbrownfoxjumpsoverthelazydog";
StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.Length; i++)
{
if (i % 2 == 0)
{
sb.Append(s[i].ToString().ToUpper());
}
else
{
sb.Append(s[i].ToString());
}
}
sb.ToString().Dump();
Output will be;
ThEqUiCkBrOwNfOxJuMpSoVeRtHeLaZyDoG
Another possible solution with LINQ can be done in one line like this:
string s = "thequickbrownfoxjumpsoverthelazydog";
string result = new String(s
// take each character
.ToCharArray()
// convert every character at even index to upper
.Select ((character, index) => (index % 2) == 0 ? Char.ToUpper(character) : character)
// back to array in order to create a string
.ToArray());
Console.WriteLine(result);
The output is:
ThEqUiCkBrOwNfOxJuMpSoVeRtHeLaZyDoG
This solution uses the indexed LINQ Select clause in order to access the current index and the value that is currently projected.
A one liner:
new string(myString.Select((c, i) => i % 2 == 0 ? char.ToUpper(c) : c).ToArray())
An extension method:
public static string AltCase(this string s)
{
return new string(s.Select((c, i) => i % 2 == 0 ? char.ToUpper(c) : c).ToArray());
}