I'm trying to create a method which takes two parameters, "word" and "input". The aim of the method is to print any word where all of its characters can be found in "input" no more than once (this is why the character is removed if a letter is found).
Not all the letters from "input" must be in "word" - eg, for input = "cacten" and word = "ace", word would be printed, but if word = "aced" then it would not.
However, when I run the program it produces unexpected results (words being longer than "input", containing letters not found in "input"), and have coded the solution several ways all with the same outcome. This has stumped me for hours and I cannot work out what's going wrong. Any and all help will be greatly appreciated, thanks. My full code for the method is written below.
static void Program(string input, string word)
{
int letters = 0;
List<string> remaining = new List<string>();
foreach (char item in input)
{
remaining.Add(item.ToString());
}
input = remaining.ToString();
foreach (char letter in word)
{
string c = letter.ToString();
if (input.Contains(c))
{
letters++;
remaining.Remove(c);
input = remaining.ToString();
}
}
if (letters == word.Length)
{
Console.WriteLine(word);
}
}
Ok so just to go through where you are going wrong.
Firstly when you assign remaining.ToString() to your input variable. What you actually assign is this System.Collections.Generic.List1[System.String]. Doing to ToString on a List just gives you the the type of list it is. It doesnt join all your characters back up. Thats probably the main thing that is casuing you issues.
Also you are forcing everything into string types and really you don't need to a lot of the time, because string already implements IEnumerable you can get your string as a list of chars by just doing myString.ToList()
So there is no need for this:
foreach (char item in input)
{
remaining.Add(item.ToString());
}
things like string.Contains have overloads that take chars so again no need for making things string here:
foreach (char letter in word)
{
string c = letter.ToString();
if (input.Contains(c))
{
letters++;
remaining.Remove(c);
input = remaining.ToString();
}
}
you can just user the letter variable of type char and pass that into contains and beacuse remaining is now a List<char> you can remove a char from it.
again Don't reassign remaining.ToString() back into input. use string.Join like this
string.Join(string.empty,remaining);
As someone else has posted there is a probably better ways of doing this, but I hope that what I've put here helps you understand what was going wrong and will help you learn
You can also use Regular Expression which was created for such scenarios.
bool IsMatch(string input, string word)
{
var pattern = string.Format("\\b[{0}]+\\b", input);
var r = new Regex(pattern);
return r.IsMatch(word);
}
I created a sample code for you on DotNetFiddle.
You can check what the pattern does at Regex101. It has a pretty "Explanation" and "Quick Reference" panel.
There are a lot of ways to achieve that, here is a suggestion:
static void Main(string[] args)
{
Func("cacten","ace");
Func("cacten", "aced");
Console.ReadLine();
}
static void Func(string input, string word)
{
bool isMatch = true;
foreach (Char s in word)
{
if (!input.Contains(s.ToString()))
{
isMatch = false;
break;
}
}
// success
if (isMatch)
{
Console.WriteLine(word);
}
// no match
else
{
Console.WriteLine("No Match");
}
}
Not really an answer to your question but its always fun to do this sort of thing with Linq:
static void Print(string input, string word)
{
if (word.All(ch => input.Contains(ch) &&
word.GroupBy(c => c)
.All(g => g.Count() <= input.Count(c => c == g.Key))))
Console.WriteLine(word);
}
Functional programming is all about what you want without all the pesky loops, ifs and what nots... Notice that this code does what you'd do in your head without needing to painfully specify step by step how you'd actually do it:
Make sure all characters in word are in input.
Make sure all characters in word are used at most as many times as they are present in input.
Still, getting the basics right is a must, posted this answer as additional info.
Related
I am learning Dotnet c# on my own.
how to find whether a given text exists or not in a string and if exists, how to find count of times the word has got repeated in that string. even if the word is misspelled, how to find it and print that the word is misspelled?
we can do this with collections or linq in c# but here i used string class and used contains method but iam struck after that.
if we can do this with help of linq, how?
because linq works with collections, Right?
you need a list in order to play with linq.
but here we are playing with string(paragraph).
how linq can be used find a word in paragraph?
kindly help.
here is what i have tried so far.
string str = "Education is a ray of light in the darkness. It certainly is a hope for a good life. Eudcation is a basic right of every Human on this Planet. To deny this right is evil. Uneducated youth is the worst thing for Humanity. Above all, the governments of all countries must ensure to spread Education";
for(int i = 0; i < i++)
if (str.Contains("Education") == true)
{
Console.WriteLine("found");
}
else
{
Console.WriteLine("not found");
}
You can make a string a string[] by splitting it by a character/string. Then you can use LINQ:
if(str.Split().Contains("makes"))
{
// note that the default Split without arguments also includes tabs and new-lines
}
If you don't care whether it is a word or just a sub-string, you can use str.Contains("makes") directly.
If you want to compare in a case insensitive way, use the overload of Contains:
if(str.Split().Contains("makes", StringComparer.InvariantCultureIgnoreCase)){}
string str = "money makes many makes things";
var strArray = str.Split(" ");
var count = strArray.Count(x => x == "makes");
the simplest way is to use Split extension to split the string into an array of words.
here is an example :
var words = str.Split(' ');
if(words.Length > 0)
{
foreach(var word in words)
{
if(word.IndexOf("makes", StringComparison.InvariantCultureIgnoreCase) != -1)
{
Console.WriteLine("found");
}
else
{
Console.WriteLine("not found");
}
}
}
Now, since you just want the count of number word occurrences, you can use LINQ to do that in a single line like this :
var totalOccurrences = str.Split(' ').Count(x=> x.IndexOf("makes", StringComparison.InvariantCultureIgnoreCase) != -1);
Note that StringComparison.InvariantCultureIgnoreCase is required if you want a case-insensitive comparison.
I was trying to create a list from a user input with something like this:
Create newlist: word1, word2, word3, etc...,
but how do I get those words one by one only by using commas as references going through them (in order) and placing them into an Array etc? Example:
string Input = Console.ReadLine();
if (Input.Contains("Create new list:"))
{
foreach (char character in Input)
{
if (character == ',')//when it reach a comma
{
//code goes here, where I got stuck...
}
}
}
Edit: I didn`t know the existence of "Split" my mistake... but at least it would great if you could explain me to to use it for the problem above?
You can use this:
String words = "word1, word2, word3";
List:
List<string> wordsList= words.Split(',').ToList<string>();
Array:
string[] namesArray = words.Split(',');
#patrick Artner beat me to it, but you can just split the input with the comma as the argument, or whatever you want the argument to be.
This is the example, and you will learn from the documentation.
using System;
public class Example {
public static void Main() {
String value = "This is a short string.";
Char delimiter = 's';
String[] substrings = value.Split(delimiter);
foreach (var substring in substrings)
Console.WriteLine(substring);
}
}
The example displays the following output:
Thi
i
a
hort
tring.
I have a list of bad words, that if found in the text string, will be replaced by a cleaned word.
eg. badwords{woof} is replaced by w$$f
But is currently only working when the array list is in the same case as the matched word in the sentence.
var badWords = new List<string>{"woof", "meow"}
var string = "I have a cat named meow and a dog name Woof."
Should become === "I have a cat named m$$w and a dog name W$$f"
public string CensorText(string text)
{
if (string.IsNullOrWhiteSpace(text))
{
return text;
}
foreach (string word in CensoredWords)
{
text = text.Replace(word, WordCleaner(word));
}
return text;
}
private static string WordCleaner(string wordToClean)
{
string firstChar = wordToClean.Substring(0,1);
string lastChar = wordToClean.Substring(wordToClean.Length - 1);
string centerHash = new string('$', wordToClean.Length-2);
return string.Concat(firstChar, centerHash, lastChar);
}
How can make it so that its case insensitive when looping through the words and cleaning them. Simpler the answer is better.
Try replacing:
text = text.Replace(word, WordCleaner(word));
with
text = text.Replace(word.ToLower(), WordCleaner(word));
This converts any upper case letter to a lower case one.
Edit
I've realised that I've made the wrong variable into lower case.
Change:
public string CensorText(string text)
{
To:
public string CensorText(string text)
{
text = text.ToLower();
Edit 2
To retain the original sentence with the censored words changed, it would be much easier to use re instead. First, revert your file back to how it was in the question.
Now replace:
text = text.Replace(word, WordCleaner(word));
with:
text = regex.replace(text,word,WordCleaner(word),RegexOptions.Ignorecase);
Here's a simple option you can use.
The benefit is you don't care which of the word is lower case, it'll work for either cases. Note that compare returns an int, hence why we check it's 0 for a match.
string input = "the Woof is on Fire, we don't need no bucket, leT the ...";
string[] bad_words = new string[] {"woof","fire","BucKet", "Let"};
foreach (var word in input.Split(' ')) {
if (bad_words.Any( b => String.Compare( word, b // Following line does what you want:
, StringComparison.OrdinalIgnoreCase) == 0))
Console.Write(WordCleaner(word));
else
Console.Write(word);
}
Output:
the W$$f is on F$$e we don't need no b$$$$t l$T the ...
Seems fine to me. Note that if you split on space, a word with a comma right after will have that comma as part of the word
Okay, so I'm creating a hangman game and everything functions so far, including what I'm TRYING to do in the question.
But it feels like there is a much more efficient method of obtaining the char that is also easier to manipulate the index.
protected static void alphabetSelector(string activeWordAlphabet)
{
char[] activeWord = activeWordAlphabet.ToCharArray();
string activeWordString = new string(activeWord);
Console.WriteLine("If you'd like to guess a letter, enter the letter. \n
If you'd like to guess the word, please type in the word. --- testing answer{0}",
activeWordString);
//Console.WriteLine("For Testing Purposes ONLY");
String chosenLetter = Console.ReadLine();
//Char[] letterFinder = Array.FindAll(activeWord, s => s.Equals(chosenLetter));
//string activeWordString = new string(activeWord);
foreach (char letter in activeWord);
{
if(activeWordString.Contains(chosenLetter))
{
Console.WriteLine("{0}", activeWordString);
Console.ReadLine();
}
else
{
Console.WriteLine("errrr...wrong!");
Console.ReadLine();
}
}
}
I have broken up the code in some areas to prevent the reader from having to scroll sideways. If this is bothersome, please let me know and I'll leave it in the future.
So this code will successfully print out the 'word' whenever I select the correct letter from the random word (I have the console print the actual word so that I can test it successfully each time). It will also print 'wrong' when I choose a letter NOT in the string.
But I feel like I should be able to use the
Array.FindAll(activeWord, ...)
functionality or some other way. But every time I try and reorder the arguments, it gives me all kinds of different errors and tells me to redo my arguments.
So, if you can look at this and find an easier method of searching the actual array for the user-selected 'letter', please help!! Even if it's not using the Array.FindAll method!!
Edit
Okay, it seems like there's some confusion with what I've done and why I've done it.
I'm ONLY printing the word inside that 'if' statement to test and make sure that the foreach{if{}} will actually work to find the char inside the string. But I ultimately need to be able to provide a placeholder for a char that is successfully found, as well as being able to 'cross out' the letter (from the alphabet list not shown here).
It's hangman - surely you guys know what I'm needing it to do. It has to keep track of which letters are left in the word, which letters have been chosen, as well as which letters are left in the entire alphabet.
I'm a 4-day old newb when it comes to programming, so please. . . I'm only doing what I know to do and when I get errors, I comment things out and write more until I find something that works.
Take a look at this demo I put together for you: https://dotnetfiddle.net/eP9TQM
I'd suggest creating a second string for the display string. Use a StringBuilder, and you can replace the characters in it at specific indices while creating the fewest number of stringobjects in the process.
string word = "your word or phrase here";
//Initialize a new StringBuilder that will display the word with placeholders.
StringBuilder display = new StringBuilder(word.Length); //You know the display word is the same length as the original word
display.Append('-', word.Length); //Fill it with placeholders.
So now you have your phrase/word, and a string builder full of characters that need to be discovered.
Go ahead and convert the display StringBuilder to a string that you can check on each pass to see if it equals your word:
var displayString = display.ToString();
//Loop until the display string is equal to the word
while (!displayString.Equals(word))
{
//Inside here your logic will follow.
}
So you are basically looping until the person answers here. You could of course go back and add logic to limit the number of attempts, or whatever you desire as an alternate exit strategy.
Inside this logic, you will check if they guessed a letter or a word based on how many characters they entered.
If they guessed a word, the logic is simple. Check if the guessed word is the same as the hidden word. If it is, then you break the loop and they are done. Otherwise, guessing loops back around.
If they guessed a letter, the logic is pretty straightforward, but more involved.
First get the character they guessed, just because it may be easier to work with this way.
char guess = input[0];
Now, look over the word for instances of that character:
//Look for instances of the character in the word.
for (int i = 0; i < word.Length; ++i)
{
//If the current index in the word matches their guess, then update the display.
if (char.ToUpperInvariant(word[i]) == char.ToUpperInvariant(guess))
display[i] = word[i];
}
The comments above should explain the idea here.
Update your displayString at the bottom of the loop so that it will check against the hidden word again:
displayString = display.ToString();
That's really all you need to do here. No fancy Linq needed.
Ok your code is really confusing, even with your edit.
First, why these 2 lines of code since activeWordAlphabet is a string :
char[] activeWord = activeWordAlphabet.ToCharArray();
string activeWordString = new string(activeWord);
Then you do your foreach.
For the word "FooBar", if the player types 'F', you will print
FooBar
FooBar
FooBar
FooBar
FooBar
FooBar
How does this help you in anything?
I think you have to review your algorithm. The string type have the function you need
int chosenLetterPosition = activeWord.IndexOf(chosenLetter, alreadyFoundPosition)
alreadyFoundPosition is an int from where the function will search the letter
IndexOf() returns -1 if the letter is not find or a positive number.
You can save this position with your letter in a dictionary to use it again as your new 'alreadyFoundPosition' if the chosenLetter is already in the dictionary
This is my answer. Because I don't have a lot of tasks today :)
class Letter
{
public bool ischosen { get; set; }
public char value { get; set; }
}
class LetterList
{
public LetterList(string word)
{
_lst = new List<Letter>();
word.ToList().ForEach(x => _lst.Add(new Letter() { value = x }));
}
public bool FindLetter(char letter)
{
var search = _lst.Where(x => x.value == letter).ToList();
search.ForEach(x=>x.ischosen=true);
return search.Count > 0 ? true : false;
}
public string NotChosen()
{
var res = "";
_lst.Where(x => !x.ischosen).ToList().ForEach(x => { res += x.value; });
return res;
}
List<Letter> _lst;
}
How to use
var abc = new LetterList("abcdefghijklmnopqrstuvwxyz");
var answer = new LetterList("myanswer");
Console.WriteLine("This my question. Why? write your answer please");
char x = Console.ReadLine()[0];
if (answer.FindLetter(x))
{
Console.WriteLine("you are right!");
}
else
{
Console.WriteLine("fail");
}
abc.FindLetter(x);
Console.WriteLine("not chosen abc:{0} answer:{1}", abc.NotChosen(), answer.NotChosen());
At least we used to play this game like that when i was a child.
I would like to check some string for invalid characters. With invalid characters I mean characters that should not be there. What characters are these? This is different, but I think thats not that importan, important is how should I do that and what is the easiest and best way (performance) to do that?
Let say I just want strings that contains 'A-Z', 'empty', '.', '$', '0-9'
So if i have a string like "HELLO STaCKOVERFLOW" => invalid, because of the 'a'.
Ok now how to do that? I could make a List<char> and put every char in it that is not allowed and check the string with this list. Maybe not a good idea, because there a lot of chars then. But I could make a list that contains all of the allowed chars right? And then? For every char in the string I have to compare the List<char>? Any smart code for this? And another question: if I would add A-Z to the List<char> I have to add 25 chars manually, but these chars are as I know 65-90 in the ASCII Table, can I add them easier? Any suggestions? Thank you
You can use a regular expression for this:
Regex r = new Regex("[^A-Z0-9.$ ]$");
if (r.IsMatch(SomeString)) {
// validation failed
}
To create a list of characters from A-Z or 0-9 you would use a simple loop:
for (char c = 'A'; c <= 'Z'; c++) {
// c or c.ToString() depending on what you need
}
But you don't need that with the Regex - pretty much every regex engine understands the range syntax (A-Z).
I have only just written such a function, and an extended version to restrict the first and last characters when needed. The original function merely checks whether or not the string consists of valid characters only, the extended function adds two integers for the numbers of valid characters at the beginning of the list to be skipped when checking the first and last characters, in practice it simply calls the original function 3 times, in the example below it ensures that the string begins with a letter and doesn't end with an underscore.
StrChr(String, "_0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"));
StrChrEx(String, "_0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ", 11, 1));
BOOL __cdecl StrChr(CHAR* str, CHAR* chars)
{
for (int s = 0; str[s] != 0; s++)
{
int c = 0;
while (true)
{
if (chars[c] == 0)
{
return false;
}
else if (str[s] == chars[c])
{
break;
}
else
{
c++;
}
}
}
return true;
}
BOOL __cdecl StrChrEx(CHAR* str, CHAR* chars, UINT excl_first, UINT excl_last)
{
char first[2] = {str[0], 0};
char last[2] = {str[strlen(str) - 1], 0};
if (!StrChr(str, chars))
{
return false;
}
if (excl_first != 0)
{
if (!StrChr(first, chars + excl_first))
{
return false;
}
}
if (excl_last != 0)
{
if (!StrChr(last, chars + excl_last))
{
return false;
}
}
return true;
}
If you are using c#, you do this easily using List and contains. You can do this with single characters (in a string) or a multicharacter string just the same
var pn = "The String To ChecK";
var badStrings = new List<string>()
{
" ","\t","\n","\r"
};
foreach(var badString in badStrings)
{
if(pn.Contains(badString))
{
//Do something
}
}
If you're not super good with regular expressions, then there is another way to go about this in C#. Here is a block of code I wrote to test a string variable named notifName:
var alphabet = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z";
var numbers = "0,1,2,3,4,5,6,7,8,9";
var specialChars = " ,(,),_,[,],!,*,-,.,+,-";
var validChars = (alphabet + "," + alphabet.ToUpper() + "," + numbers + "," + specialChars).Split(',');
for (int i = 0; i < notifName.Length; i++)
{
if (Array.IndexOf(validChars, notifName[i].ToString()) < 0) {
errorFound = $"Invalid character '{notifName[i]}' found in notification name.";
break;
}
}
You can change the characters added to the array as needed. The Array IndexOf method is the key to the whole thing. Of course if you want commas to be valid, then you would need to choose a different split character.
Not enough reps to comment directly, but I recommend the Regex approach. One small caveat: you probably need to anchor both ends of the input string, and you will want at least one character to match. So (with thanks to ThiefMaster), here's my regex to validate user input for a simple arithmetical calculator (plus, minus, multiply, divide):
Regex r = new Regex(#"^[0-9\.\-\+\*\/ ]+$");
I'd go with a regex, but still need to add my 2 cents here, because all the proposed non-regex solutions are O(MN) in the worst case (string is valid) which I find repulsive for religious reasons.
Even more so when LINQ offers a simpler and more efficient solution than nesting loops:
var isInvalid = "The String To Test".Intersect("ALL_INVALID_CHARS").Any();