Before getting into C# I used to study Python. I did this small project where the program makes a list and whatever you type it is added to the list. I tried to do the same in C# as a form of practice, but I seem to be doing something, if not everything, for the program won't work. This is my code:
using System;
using System.Collections.Generic:
class idk
{
static void Main(string[] args)
{
List<string> list = new List<string>();
for ( ; true; )
{
Console.Write("Tell me something: ");
var inp = Console.ReadLine();
list.Add(inp);
var i = 1;
foreach (string a in list)
var ni = i + 1;
Console.WriteLine(String.Format("{0}. {1}", ni, a));
}
}
}
So I want my program to take the input, save it in the list, and then print the list but in the form of (e.g.)
Idk
C
A
Like an actual list, where you number each item and all that. So I tried to do the same I did in Python:
List = []
while True:
item = input("Tell me something: ")
List.append(item)
i = 1
for val in List:
print(f"{i}. {val}")
i += 1
Is there something I can edit from my code to make it do the same? Or perhaps I may need to rewrite the whole thing? Thanks for your help.
I suggest loop type changing from foreach to for:
for (int i = 0; i < list.Count; ++i)
Console.WriteLine($"{i + 1}. {list[i]}");
If you insist on foreach:
int index = 0;
foreach (var item in list)
Console.WriteLine($"{++index}. {item}");
You can print the list in one go with a help of Join (to join list's items) and Linq (to query the list):
Console.WriteLine(string.Join(Environment.NewLine, list
.Select((value, index) => $"{index + 1}. {value}")));
I think you should only print the contents of the list at the end when the user has decided they don't want to enter anything anymore:
using System;
using System.Collections.Generic;
class MainClass {
public static void Main (string[] args) {
List<string> strList = new List<string>();
while (true) {
Console.Write("Tell me something: ");
var str = Console.ReadLine();
if (String.IsNullOrWhiteSpace(str)) {
break;
}
strList.Add(str);
}
for (var i = 0; i < strList.Count; i++) {
Console.WriteLine(String.Format("{0}. {1}", i + 1, strList[i]));
}
}
}
Example Usage:
Tell me something: idk
Tell me something: C
Tell me something: A
Tell me something:
1. idk
2. C
3. A
Try it here.
Related
I'm trying to find if i can add an item in list in specific position.
Example
string[] tokens= new string[10];
tokens[5]="TestString";
when i'm trying this to list
List<string> mitems = new List<string>();
mitems.Insert(5, "TestString");
I'm getting error list inside a list index out of range.
Is there any relative to this for a list?
Use the Insert(index, item); method.
Have a look at MSDN Insert for more information.
But you will get an error when you're trying to insert an item at an index which is not existing.
You could init your list with 10 empty values like you did with your array but if you use Insert a new entry is created and not an old replaced like with a dictionary. That would mean you would have 11 entries after the first use of Insert
This example code
var items = new List<string>();
items.AddRange(Enumerable.Repeat(string.Empty, 10));
Console.WriteLine(items.Count);
items.Insert(5, "TestString");
Console.WriteLine(items.Count);
gives this output (for better understanding):
10
11
private static void Myfunc()
{
List<string> l = new List<string>();
string opt = "y";
while (opt == "y")
{
Console.WriteLine("Do you want to add in a specific position? (y/n)");
string pos = Console.ReadLine();
if (pos == "y")
{
Console.WriteLine("Which index you want to add?");
int index = Convert.ToInt16(Console.ReadLine());
Console.WriteLine("Add items in {0}", index);
l.Insert(index, Console.ReadLine());
}
else
{
Console.WriteLine("Enter to add in a list");
l.Add(Console.ReadLine());
Console.WriteLine("Do you wish to continue? (y/n)");
opt = Console.ReadLine();
}
Console.WriteLine("Do you want to print the list? (y/n)");
string print = Console.ReadLine();
if (print == "y")
{
foreach (var item in l)
{
Console.WriteLine(item);
}
}
}
I wrote this function for you.
Add this function to a console app for better understanding how list works for insert and append
EDIT 1:
I just saw your edit, another way of initializing a list with default values and then insert something in a certain position would be by initializing the list like this :-
List<string> l = Enumerable.Repeat("something blank", 10).ToList();
And then add to an index of your choice
Following adds default values of string at every index from 0-9
string[] tokens= new string[10];
But list is created on heap nothing instantiated. No default assigned values.
List<string> mitems = new List<string>();
If you try following it will fail as there are no values at 0-5
mitems.Insert(5, "TestString");
If you do following it will work
mitems.Insert(0, "TestString");
You can use List<T>.Insert(int, T) method to do that, example:
var tokens = new List<string>();
for (int i = 0; i < 10; i++)
tokens.Add(string.Empty);
tokens.Insert(5, "TestString");
See MSDN
Edit:
If you were just trying to replace the item in index of 5, than the [] will also do the trick as following example:
var tokens = new List<string>(10);
for (int i = 0; i < 10; i++)
tokens.Add(string.Empty);
tokens[5] = "TestString";
I would like to pass two string lists (one namd checkeds and one named remaining) as arguments to program but I can't figure out how. Thanks in advance for any help.
This is what I tried lastly :
static void Main(List<string> args)
{
List<string> checkeds = new List<string>();
List<string> remaining = new List<string>();
int listCount = 0;
foreach(List<string> list in args)
{
listCount++;
if (listCount == 1)
foreach (string item in list)
checkeds.Add(item);
else if (listCount == 2)
foreach (string item in list)
remaining.Add(item);
}
}
The parameter to Main to receive command line arguments is always string[]. You can't use List<string> instead.
I'd suggest that if you want two lists of strings, you just have each list as a single command line argument, separated by commas:
using System;
using System.Collections.Generic;
class Program
{
static void Main(string[] args)
{
if (args.Length != 2)
{
Console.WriteLine("Required arguments: <list of checked> <list of remaining>");
return;
}
var checkedList = new List<string>(args[0].Split(','));
var remainingList = new List<string>(args[1].Split(','));
Console.WriteLine("Checked items:");
foreach (var item in checkedList)
{
Console.WriteLine($" {item}");
}
Console.WriteLine("Remaining items:");
foreach (var item in remainingList)
{
Console.WriteLine($" {item}");
}
}
}
Then if you run it like this:
Program.exe a,b,c d,e,f,g
You'll get output of:
Checked items:
a
b
c
Remaining items:
d
e
f
g
I would suggest passing a comma separated(or some other delimiter) and then split them in the Main method like this
List<string> checkeds = args[0].Split(',').ToList();
List<string> remaining = args[1].Split(',').ToList();
-- Futher processing ...
You need to pass values to your app like
AppName a,b,c,d e,f,g,h
What I'm trying to do is the following - I have hundreds of log files, that I need to search through and do some counting. The basic idea is this, take a .txt file, read every line, if search item 1 is found, increment the counter for search item 1, if search item 2 is found, increment the counter for search item 2 and so on.. For example, if the file contained something like...
a b c
d e f
g h i
j k h
And If I specified the searchables to be e & h, the output should say
e : 1
h : 2
The number of search terms is expandable, basically the user can give either 1 search number or 10, so i'm not sure how I can implement n number of counters based on the number of searchables.
The below is what I have so far, its just a basic approach to see what works and what doesnt... Right now, it only keeps the count for one of the search terms. At the moment, I am writing the results to the console to just test, ultimately, It will be written to a .txt or .xlsx. any help will be appreciated!
string line;
int Scounter = 0;
int Mcounter = 0;
List<string> searchables = new List<string>();
private void search_Log(string p)
{
searchables.Add("S");
searchables.Add("M");
StreamReader reader = new StreamReader(p);
while ((line = reader.ReadLine()) != null)
{
for (int i = 0; i < searchables.Count(); i++)
{
if (line.Contains(searchables[i]))
{
Scounter++;
}
}
}
reader.Close();
Console.WriteLine("# of S: " + Scounter);
Console.WriteLine("# of M: " + Mcounter);
}
A common approach to this is to use a Dictionary<string, int> to track the values and counts:
// Initialise the dictionary:
Dictionary<string, int> counters = new Dictionary<string, int>();
Then later:
if (line.Contains(searchables[i]))
{
if (counters.ContainsKey(searchables[i]))
{
counters[searchables[i]] ++;
}
else
{
counters.Add(searchables[i], 1);
}
}
Then, when you are finished processing:
// Add in any searches which had no results:
foreach (var searchTerm in searchables)
{
if (counters.ContainsKey(searchTerm) == false)
{
counters.Add(searchTerm, 0);
}
}
foreach (var item in counters)
{
Console.WriteLine("Value {0} occurred {1} times", item.Key, item.Value);
}
you could use a class for the searchables like:
public class Searchable
{
public string searchTerm;
public int count;
}
then
while ((line = reader.ReadLine()) != null)
{
foreach (var searchable in searchables)
{
if (line.Contains(searchable.searchTerm))
{
searchable.count++;
}
}
}
This would be one of many ways to track multiple search terms and their counts.
You can make use of linq here:
string lines = reader.ReadtoEnd();
var result = lines.Split(new string[]{" ","\r\n"},StringSplitOptions.RemoveEmptyEntries)
.GroupBy(x=>x)
.Select(g=> new
{
Alphabet = g.Key ,
Count = g.Count()
}
);
Input:
a b c
d e f
Output :
a: 1
b: 1
c: 1
d: 1
e: 1
f: 1
This version will count 1^n search terms that occur 1^n times per file line. It accounts for the possibility of a term existing more than once on one line.
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication5
{
class Program
{
static void Main(string[] args)
{
Func<string, string[], Dictionary<string, int>> searchForCounts = null;
searchForCounts = (filePathAndName, searchTerms) =>
{
Dictionary<string, int> results = new Dictionary<string, int>();
if (string.IsNullOrEmpty(filePathAndName) || !File.Exists(filePathAndName))
return results;
using (TextReader tr = File.OpenText(filePathAndName))
{
string line = null;
while ((line = tr.ReadLine()) != null)
{
for (int i = 0; i < searchTerms.Length; ++i)
{
var searchTerm = searchTerms[i].ToLower();
var index = 0;
while (index > -1)
{
index = line.IndexOf(searchTerm, index, StringComparison.OrdinalIgnoreCase);
if (index > -1)
{
if (results.ContainsKey(searchTerm))
results[searchTerm] += 1;
else
results[searchTerm] = 1;
index += searchTerm.Length - 1;
}
}
}
}
}
return results;
};
var counts = searchForCounts("D:\\Projects\\ConsoleApplication5\\ConsoleApplication5\\TestLog.txt", new string[] { "one", "two" });
Console.WriteLine("----Counts----");
foreach (var keyPair in counts)
{
Console.WriteLine("Term: " + keyPair.Key.PadRight(10, ' ') + " Count: " + keyPair.Value.ToString());
}
Console.ReadKey(true);
}
}
}
Input:
OnE, TwO
Output:
----Counts----
Term: one Count: 7
Term: two Count: 15
The purpose of my program is to take a data txt file and edit it, and/or make additions and subtractions to it.
The text file format is like this:
Name|Address|Phone|# of people coming|isRSVP
The code I have seems to be doing it's job all the way up until I try to click one of the names within a listbox and it needs to search through the multidimensional array to pull information out and place within a set of textboxes where they can be edited. The problem is that the foreach loop I use gives me an out of bounds exception. I tried to do a step into debug to make sure the data is correct in the array and see the process. Everything seems to do correctly but for some reason in the conditional statement person[0]==listbox1.selectedIndex isn't returning true even though both are the same as I seen through the step into process. Any help would be greatly appreciated.
This is my code:
StringBuilder newFile = new StringBuilder();
static string txtList= "guest_list.txt";
static string[] file = File.ReadAllLines(txtList);
static int x = file.Count();
string[,] list = new string[x ,5];
public void loadGuestList()
{
int count2 = 0;
foreach (string line in file)
{
string[] sliced = line.Split('|');
int count = 0;
list[count2, count] = sliced[0];
count++;
list[count2, count] = sliced[1];
count++;
list[count2,count] = sliced[2];
count++;
list[count2,count]= sliced[3];
count++;
list[count2, count] = sliced[4];
count++;
listBox1.Items.Add(list[count2,0]);
count2++;
}
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
foreach (string person in list)
{
if ( person[0].ToString()==listBox1.SelectedItem.ToString())
{
addTxt.Text = char.ToString(person[1]);
textPhone.Text = char.ToString(person[2]);
textPeople.Text = char.ToString(person[3]);
if (person[4] == 'n' )
{
}
else
{
chkRSVP.Checked = true;
}
break;
}
}
}
The problem lies in this line:
foreach (string person in list)
The list is defined as being string[,] which when you for each over will do every element, not just the column of data. You really should do something such as:
for(int index = 0; index <= list.GetUpperBound(0); index++)
{
string slice1 = list[index, 0];
string slice2 = list[index, 1];
....
}
or switch to using a Dictionary<string, string[]>().
Try to use a "Person" object and override equals(). Right now you're trying to put your multidimensional array (list[0]) into a string, it'll give you a unwanted result. You should use list[0,0] instead.
In agreement with Adam Gritt, I tested the following code and it seemed to work:
using System;
namespace so_foreach_bounds
{
class MainClass
{
public static void Main (string[] args)
{
//System.Text.StringBuilder newFile = new System.Text.StringBuilder();
string txtList= "guest_list.txt";
string[] file = System.IO.File.ReadAllLines(txtList);
int x = file.Length;
System.Collections.Generic.List<string[]> list = new System.Collections.Generic.List<string[]> ();
foreach (string line in file)
{
string[] sliced = line.Split('|');
list.Add(sliced);
}
foreach (string[] person in list)
{
Console.WriteLine (String.Join(", ", person));
if (person[0] =="Gary")
{
string txtAdd = person[1];
string txtPhone = person[2];
string txtpeople = person[3];
if (person[4] == "n" )
{
}
else
{
bool has_resvped = true;
}
break;
}
}
}
}
}
The issue is how you are iterating over the 2d array. It is usually a better idea to create a "Person" class, than try to manage it via arrays though. Oh yes, and it's usually a good idea to check that a list box item is selected before attempting to use one of its members.
I really cant understand how to make a simple algorithm on C# to solve my problem. So, we have a sentences:
{Hello|Hi|Hi-Hi} my {mate|m8|friend|friends}.
So, my program should make a lot of sentences looks like:
Hello my mate.
Hello my m8.
Hello my friend.
Hello my friends.
Hi my mate.
...
Hi-Hi my friends.
I know, there are a lot of programs which could do this, but i'd like to make it myself. Ofcourse, it should work with this too:
{Hello|Hi|Hi-Hi} my {mate|m8|friend|friends}, {i|we} want to {tell|say} you {hello|hi|hi-hi}.
Update I just wasn't too happy about my using the regexen to parse so simple input; yet I disliked the manual index manipulation jungle found in other answers.
So I replaced the tokenizing with a Enumerator-based scanner with two alternating token-states. This is more justified by the complexity of the input, and has a 'Linqy' feel to it (although it really isn't Linq). I have kept the original Regex based parser at the end of my post for interested readers.
This just had to be solved using Eric Lippert's/IanG's CartesianProduct Linq extension method, in which the core of the program becomes:
public static void Main(string[] args)
{
const string data = #"{Hello|Hi|Hi-Hi} my {mate|m8|friend|friends}, {i|we} want to {tell|say} you {hello|hi|hi-hi}.";
var pockets = Tokenize(data.GetEnumerator());
foreach (var result in CartesianProduct(pockets))
Console.WriteLine(string.Join("", result.ToArray()));
}
Using just two regexen (chunks and legs) to do the parsing into 'pockets', it becomes a matter of writing the CartesianProduct to the console :) Here is the full working code (.NET 3.5+):
using System;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;
using System.Collections.Generic;
namespace X
{
static class Y
{
private static bool ReadTill(this IEnumerator<char> input, string stopChars, Action<StringBuilder> action)
{
var sb = new StringBuilder();
try
{
while (input.MoveNext())
if (stopChars.Contains(input.Current))
return true;
else
sb.Append(input.Current);
} finally
{
action(sb);
}
return false;
}
private static IEnumerable<IEnumerable<string>> Tokenize(IEnumerator<char> input)
{
var result = new List<IEnumerable<string>>();
while(input.ReadTill("{", sb => result.Add(new [] { sb.ToString() })) &&
input.ReadTill("}", sb => result.Add(sb.ToString().Split('|'))))
{
// Console.WriteLine("Expected cumulative results: " + result.Select(a => a.Count()).Aggregate(1, (i,j) => i*j));
}
return result;
}
public static void Main(string[] args)
{
const string data = #"{Hello|Hi|Hi-Hi} my {mate|m8|friend|friends}, {i|we} want to {tell|say} you {hello|hi|hi-hi}.";
var pockets = Tokenize(data.GetEnumerator());
foreach (var result in CartesianProduct(pockets))
Console.WriteLine(string.Join("", result.ToArray()));
}
static IEnumerable<IEnumerable<T>> CartesianProduct<T>(this IEnumerable<IEnumerable<T>> sequences)
{
IEnumerable<IEnumerable<T>> emptyProduct = new[] { Enumerable.Empty<T>() };
return sequences.Aggregate(
emptyProduct,
(accumulator, sequence) =>
from accseq in accumulator
from item in sequence
select accseq.Concat(new[] {item}));
}
}
}
Old Regex based parsing:
static readonly Regex chunks = new Regex(#"^(?<chunk>{.*?}|.*?(?={|$))+$", RegexOptions.Compiled);
static readonly Regex legs = new Regex(#"^{((?<alternative>.*?)[\|}])+(?<=})$", RegexOptions.Compiled);
private static IEnumerable<String> All(this Regex regex, string text, string group)
{
return !regex.IsMatch(text)
? new [] { text }
: regex.Match(text).Groups[group].Captures.Cast<Capture>().Select(c => c.Value);
}
public static void Main(string[] args)
{
const string data = #"{Hello|Hi|Hi-Hi} my {mate|m8|friend|friends}, {i|we} want to {tell|say} you {hello|hi|hi-hi}.";
var pockets = chunks.All(data, "chunk").Select(v => legs.All(v, "alternative"));
The rest is unchanged
Not sure what you need Linq (#user568262) or "simple" recursion (#Azad Salahli) for. Here's my take on it:
using System;
using System.Text;
class Program
{
static Random rng = new Random();
static string GetChoiceTemplatingResult(string t)
{
StringBuilder res = new StringBuilder();
for (int i = 0; i < t.Length; ++i)
if (t[i] == '{')
{
int j;
for (j = i + 1; j < t.Length; ++j)
if (t[j] == '}')
{
if (j - i < 1) continue;
var choices = t.Substring(i + 1, j - i - 1).Split('|');
res.Append(choices[rng.Next(choices.Length)]);
i = j;
break;
}
if (j == t.Length)
throw new InvalidOperationException("No matching } found.");
}
else
res.Append(t[i]);
return res.ToString();
}
static void Main(string[] args)
{
Console.WriteLine(GetChoiceTemplatingResult(
"{Hello|Hi|Hi-Hi} my {mate|m8|friend|friends}, {i|we} want to {tell|say} you {hello|hi|hi-hi}."));
}
}
As others have noted, you can solve your problem by splitting up the string into a sequence of sets, and then taking the Cartesian product of all of those sets. I wrote a bit about generating arbitrary Cartesial products here:
http://blogs.msdn.com/b/ericlippert/archive/2010/06/28/computing-a-cartesian-product-with-linq.aspx
An alternative approach, more powerful than that, is to declare a grammar for your language and then write a program that generates every string in that language. I wrote a long series of articles on how to do so. It starts here:
http://blogs.msdn.com/b/ericlippert/archive/2010/04/26/every-program-there-is-part-one.aspx
You can use a Tuple to hold index values of each collection.
For example, you would have something like:
List<string> Greetings = new List<string>()
{
"Hello",
"Hi",
"Hallo"
};
List<string> Targets = new List<string>()
{
"Mate",
"m8",
"friend",
"friends"
};
So now you have your greetings, let's create random numbers and fetch items.
static void Main(string[] args)
{
List<string> Greetings = new List<string>()
{
"Hello",
"Hi",
"Hallo"
};
List<string> Targets = new List<string>()
{
"Mate",
"m8",
"friend",
"friends"
};
var combinations = new List<Tuple<int, int>>();
Random random = new Random();
//Say you want 5 unique combinations.
while (combinations.Count < 6)
{
Tuple<int, int> tmpCombination = new Tuple<int, int>(random.Next(Greetings.Count), random.Next(Targets.Count));
if (!combinations.Contains(tmpCombination))
{
combinations.Add(tmpCombination);
}
}
foreach (var item in combinations)
{
Console.WriteLine("{0} my {1}", Greetings[item.Item1], Targets[item.Item2]);
}
Console.ReadKey();
}
This doesn't look trivial. You need to
1. do some parsing, to extract all the lists of words that you want to combine,
2. obtain all the actual combinations of these words (which is made harder by the fact that the number of lists you want to combine is not fixed)
3. rebuild the original sentence putting all the combinations in the place of the group they came from
part 1 (the parsing part) is probably the easiest: it could be done with a Regex like this
// get all the text within {} pairs
var pattern = #"\{(.*?)\}";
var query = "{Hello|Hi|Hi-Hi} my {mate|m8|friend|friends}.";
var matches = Regex.Matches(query, pattern);
// create a List of Lists
for(int i=0; i< matches.Count; i++)
{
var nl = matches[i].Groups[1].ToString().Split('|').ToList();
lists.Add(nl);
// build a "template" string like "{0} my {1}"
query = query.Replace(matches[i].Groups[1].ToString(), i.ToString());
}
for part 2 (taking a List of Lists and obtain all resulting combinations) you can refer to this answer
for part 3 (rebuilding your original sentence) you can now take the "template" string you have in query and use String.Format to substitute all the {0}, {1} .... with the combined values from part 2
// just one example,
// you will need to loop through all the combinations obtained from part 2
var OneResultingCombination = new List<string>() {"hi", "mate"};
var oneResult = string.Format(query, OneResultingCombination.ToArray());