I'm making a simple text adventure in C# and I was wondering if it was possible to read certain lines from a .txt file and assign them to a string.
I am aware of how to read all the text from a .txt file but how exactly would I assign the contents of certain lines to a string?
Have you considered the ReadAllLines method?
It returns an array of lines from which you can choose your desired line.
So for eg, if you wish to choose the 3rd line (Assuming you have 3 lines in the file):
string[] lines = File.ReadAllLines(path);
string myThirdLine= lines[2];
Probably the easiest (and cheapest in terms of memory consumption) is File.ReadLines:
String stringAtLine10 = File.ReadLines(path).ElementAtOrDefault(9);
Note that it is null if there are less than 10 lines in the file. See: ElementAtOrDefault.
It's just the concise version of a StreamReader and a counter variable which increases on every line.
As an advanced alternative: ReadLines plus some LINQ:
var lines = File.ReadLines(myFilePath).Where(MyCondition).ToArray();
where MyCondition:
bool MyCondition(string line)
{
if (line == "something")
{
return true;
}
return false;
}
In case you don't want to load all lines atonce
using(StreamReader reader=new StreamReader(path))
{
String line;
while((line=reader.ReadLine())!=null)//process temp
}
Here's a example how you can assign the lines to a string, you can't decide which line is which via fields, you have to select them yourself.
which is the line of the string you want to assign.
For example, you want line one, you define which as one and not zero, you want line eight, you define which with eight.
string getWord(int which)
{
string readed = "";
using (Systen.IO.StreamReader read = new System.IO.StreamReader("PATH HERE"))
{
readed = read.ReadToEnd();
}
string[] toReturn = readed.Split('\n');
return toReturn[which - 1];
}
Related
What I have to do is read only the second line in a .txt file and save it as a string, to use later in the code.
The file name is "SourceSetting". In line 1 and 2 I have some words
For line 1, I have this code:
string Location;
StreamReader reader = new StreamReader("SourceSettings.txt");
{
Location = reader.ReadLine();
}
ofd.InitialDirectory = Location;
And that works out great but how do I make it so that it only reads the second line so I can save it as for example:
string Text
You can skip the first line by doing nothing with it, so call ReadLine twice:
string secondLine:
using(var reader = new StreamReader("SourceSettings.txt"))
{
reader.ReadLine(); // skip
secondLine = reader.ReadLine();
}
Another way is the File class that has handy methods like ReadLines:
string secondLine = File.ReadLines("SourceSettings.txt").ElementAtOrDefault(1);
Since ReadLines also uses a stream the whole file must not be loaded into memory first to process it. Enumerable.ElementAtOrDefault will only take the second line and don't process more lines. If there are less than two lines the result is null.
Update I'd advice to go with Tim Schmelter solution.
When you call ReadLine - it moves the carret to next line. So on second call you'll read 2nd line.
string Location;
using(var reader = new StreamReader("SourceSettings.txt"))
{
Location = reader.ReadLine(); // this call will move caret to the begining of 2nd line.
Text = reader.ReadLine(); //this call will read 2nd line from the file
}
ofd.InitialDirectory = Location;
Don't forget about using.
Or an example how to do this vi ReadLines of File class if you need just one line from file. But solution with ElementAtOrDefault is the best one as Tim Schmelter points.
var Text = File.ReadLines(#"C:\Projects\info.txt").Skip(1).First()
The ReadLines and ReadAllLines methods differ as follows: When you use
ReadLines, you can start enumerating the collection of strings before
the whole collection is returned; when you use ReadAllLines, you must
wait for the whole array of strings be returned before you can access
the array. Therefore, when you are working with very large files,
ReadLines can be more efficient.
So it doesn't read all lines into memory in comparison with ReadAllLines.
The line could be read using Linq as follows.
var SecondLine = File.ReadAllLines("SourceSettings.txt").Skip(1).FirstOrDefault();
private string GetLine(string filePath, int line)
{
using (var sr = new StreamReader(filePath))
{
for (int i = 1; i < line; i++)
sr.ReadLine();
return sr.ReadLine();
}
}
Hope this will help :)
If you know that your second line is unique, because it contains a specific keyword that does not appear anywhere else in your file, you also could use linq, the benefit is that the "second" line could be any line in future.
var myLine = File.ReadLines("SourceSettings.txt")
.Where(line => line.Contains("The Keyword"))
.ToList();
I am trying to read characters from a file and then append them in another file after removing the comments (which are followed by semicolon).
sample data from parent file:
Name- Harly Brown ;Name is Harley Brown
Age- 20 ;Age is 20 years
Desired result:
Name- Harley Brown
Age- 20
I am trying the following code-
StreamReader infile = new StreamReader(floc + "G" + line + ".NC0");
while (infile.Peek() != -1)
{
letter = Convert.ToChar(infile.Read());
if (letter == ';')
{
infile.ReadLine();
}
else
{
System.IO.File.AppendAllText(path, Convert.ToString(letter));
}
}
But the output i am getting is-
Name- Harley Brown Age-20
Its because AppendAllText is not working for the newline. Is there any alternative?
Sure, why not use File.AppendAllLines. See documentation here.
Appends lines to a file, and then closes the file. If the specified file does not exist, this method creates a file, writes the specified lines to the file, and then closes the file.
It takes in any IEnumerable<string> and adds every line to the specified file. So it always adds the line on a new line.
Small example:
const string originalFile = #"D:\Temp\file.txt";
const string newFile = #"D:\Temp\newFile.txt";
// Retrieve all lines from the file.
string[] linesFromFile = File.ReadAllLines(originalFile);
List<string> linesToAppend = new List<string>();
foreach (string line in linesFromFile)
{
// 1. Split the line at the semicolon.
// 2. Take the first index, because the first part is your required result.
// 3. Trim the trailing and leading spaces.
string appendAbleLine = line.Split(';').FirstOrDefault().Trim();
// Add the line to the list of lines to append.
linesToAppend.Add(appendAbleLine);
}
// Append all lines to the file.
File.AppendAllLines(newFile, linesToAppend);
Output:
Name- Harley Brown
Age- 20
You could even change the foreach-loop into a LINQ-expression, if you prefer LINQ:
List<string> linesToAppend = linesFromFile.Select(line => line.Split(';').FirstOrDefault().Trim()).ToList();
Why use char by char comparison when .NET Framework is full of useful string manipulation functions?
Also, don't use a file write function multiple times when you can use it only one time, it's time and resources consuming!
StreamReader stream = new StreamReader("file1.txt");
string str = "";
while ((string line = infile.ReadLine()) != null) { // Get every line of the file.
line = line.Split(';')[0].Trim(); // Remove comment (right part of ;) and useless white characters.
str += line + "\n"; // Add it to our final file contents.
}
File.WriteAllText("file2.txt", str); // Write it to the new file.
You could do this with LINQ, System.File.ReadLines(string), and System.File.WriteAllLines(string, IEnumerable<string>). You could also use System.File.AppendAllLines(string, IEnumerable<string>) in a find-and-replace fashion if that was, in fact, the functionality you were going for. The difference, as the names suggest, is whether it writes everything out as a new file or if it just appends to an existing one.
System.IO.File.WriteAllLines(newPath, System.IO.File.ReadLines(oldPath).Select(c =>
{
int semicolon = c.IndexOf(';');
if (semicolon > -1)
return c.Remove(semicolon);
else
return c;
}));
In case you aren't super familiar with LINQ syntax, the idea here is to loop through each line in the file, and if it contains a semicolon (that is, IndexOf returns something that is over -1) we cut that off, and otherwise, we just return the string. Then we write all of those to the file. The StreamReader equivalent to this would be:
using (StreamReader reader = new StreamReader(oldPath))
using (StreamWriter writer = new StreamWriter(newPath))
{
string line;
while ((line = reader.ReadLine()) != null)
{
int semicolon = line.IndexOf(';');
if (semicolon > -1)
line = c.Remove(semicolon);
writer.WriteLine(line);
}
}
Although, of course, this would feed an extra empty line at the end and the LINQ version wouldn't (as far as I know, it occurs to me that I'm not one hundred percent sure on that, but if someone reading this does know I would appreciate a comment).
Another important thing to note, just looking at your original file, you might want to add in some Trim calls, since it looks like you can have spaces before your semicolons, and I don't imagine you want those copied through.
I have a text file which contains following
Name address phone salary
Jack Boston 923-433-666 10000
all the fields are delimited by the spaces.
I am trying to write a C# program, this program should read a this text file and then store it in the formatted array.
My Array is as follows:
address
salary
When ever I am trying to look in google I get is how to read and write a text file in C#.
Thank you very much for your time.
You can use File.ReadAllLines method to load the file into an array. You can then use a for loop to loop through the lines, and the string type's Split method to separate each line into another array, and store the values in your formatted array.
Something like:
static void Main(string[] args)
{
var lines = File.ReadAllLines("filename.txt");
for (int i = 0; i < lines.Length; i++)
{
var fields = lines[i].Split(' ');
}
}
Do not reinvent the wheel. Can use for example fast csv reader where you can specify a delimeter you need.
There are plenty others on internet like that, just search and pick that one which fits your needs.
This answer assumes you don't know how much whitespace is between each string in a given line.
// Method to split a line into a string array separated by whitespace
private string[] Splitter(string input)
{
return Regex.Split(intput, #"\W+");
}
// Another code snippet to read the file and break the lines into arrays
// of strings and store the arrays in a list.
List<String[]> arrayList = new List<String[]>();
using (FileStream fStream = File.OpenRead(#"C:\SomeDirectory\SomeFile.txt"))
{
using(TextReader reader = new StreamReader(fStream))
{
string line = "";
while(!String.IsNullOrEmpty(line = reader.ReadLine()))
{
arrayList.Add(Splitter(line));
}
}
}
I have a .txt file with a list of 174 different strings. Each string has an unique identifier.
For example:
123|this data is variable|
456|this data is variable|
789|so is this|
etc..
I wish to write a programe in C# that will read the .txt file and display only one of the 174 strings if I specify the ID of the string I want. This is because in the file I have all the data is variable so only the ID can be used to pull the string. So instead of ending up with the example about I get just one line.
eg just
123|this data is variable|
I seem to be able to write a programe that will pull just the ID from the .txt file and not the entire string or a program that mearly reads the whole file and displays it. But am yet to wirte on that does exactly what I need. HELP!
Well the actual string i get out from the txt file has no '|' they were just in the example. An example of the real string would be: 0111111(0010101) where the data in the brackets is variable. The brackets dont exsist in the real string either.
namespace String_reader
{
class Program
{
static void Main(string[] args)
{
String filepath = #"C:\my file name here";
string line;
if(File.Exists(filepath))
{
StreamReader file = null;
try
{
file = new StreamReader(filepath);
while ((line = file.ReadLine()) !=null)
{
string regMatch = "ID number here"; //this is where it all falls apart.
Regex.IsMatch (line, regMatch);
Console.WriteLine (line);// When program is run it just displays the whole .txt file
}
}
}
finally{
if (file !=null)
file.Close();
}
}
Console.ReadLine();
}
}
}
Use a Regex. Something along the lines of Regex.Match("|"+inputString+"|",#"\|[ ]*\d+\|(.+?)\|").Groups[1].Value
Oh, I almost forgot; you'll need to substitute the d+ for the actual index you want. Right now, that'll just get you the first one.
The "|" before and after the input string makes sure both the index and the value are enclosed in a | for all elements, including the first and last. There's ways of doing a Regex without it, but IMHO they just make your regex more complicated, and less readable.
Assuming you have path and id.
Console.WriteLine(File.ReadAllLines(path).Where(l => l.StartsWith(id + "|")).FirstOrDefault());
Use ReadLines to get a string array of lines then string split on the |
You could use Regex.Split method
FileInfo info = new FileInfo("filename.txt");
String[] lines = info.OpenText().ReadToEnd().Split(' ');
foreach(String line in lines)
{
int id = Convert.ToInt32(line.Split('|')[0]);
string text = Convert.ToInt32(line.Split('|')[1]);
}
Read the data into a string
Split the string on "|"
Read the items 2 by 2: key:value,key:value,...
Add them to a dictionary
Now you can easily find your string with dictionary[key].
first load the hole file to a string.
then try this:
string s = "123|this data is variable| 456|this data is also variable| 789|so is this|";
int index = s.IndexOf("123", 0);
string temp = s.Substring(index,s.Length-index);
string[] splitStr = temp.Split('|');
Console.WriteLine(splitStr[1]);
hope this is what you are looking for.
private static IEnumerable<string> ReadLines(string fspec)
{
using (var reader = new StreamReader(new FileStream(fspec, FileMode.Open, FileAccess.Read, FileShare.Read)))
{
while (!reader.EndOfStream)
yield return reader.ReadLine();
}
}
var dict = ReadLines("input.txt")
.Select(s =>
{
var split = s.Split("|".ToArray(), 2);
return new {Id = Int32.Parse(split[0]), Text = split[1]};
})
.ToDictionary(kv => kv.Id, kv => kv.Text);
Please note that with .NET 4.0 you don't need the ReadLines function, because there is ReadLines
You can now work with that as any dictionary:
Console.WriteLine(dict[12]);
Console.WriteLine(dict[999]);
No error handling here, please add your own
You can use Split method to divide the entire text into parts sepparated by '|'. Then all even elements will correspond to numbers odd elements - to strings.
StreamReader sr = new StreamReader(filename);
string text = sr.ReadToEnd();
string[] data = text.Split('|');
Then convert certain data elements to numbers and strings, i.e. int[] IDs and string[] Strs. Find the index of the given ID with idx = Array.FindIndex(IDs, ID.Equals) and the corresponding string will be Strs[idx]
List <int> IDs;
List <string> Strs;
for (int i = 0; i < data.Length - 1; i += 2)
{
IDs.Add(int.Parse(data[i]));
Strs.Add(data[i + 1]);
}
idx = Array.FindIndex(IDs, ID.Equals); // we get ID from input
answer = Strs[idx];
I have a string in C# and would like to get text from specific line, say 65. And if file does not have so many lines I would like to get "". How to do this?
Quick and easy, assuming \r\n or \n is your newline sequence
string GetLine(string text, int lineNo)
{
string[] lines = text.Replace("\r","").Split('\n');
return lines.Length >= lineNo ? lines[lineNo-1] : null;
}
private static string ReadLine(string text, int lineNumber)
{
var reader = new StringReader(text);
string line;
int currentLineNumber = 0;
do
{
currentLineNumber += 1;
line = reader.ReadLine();
}
while (line != null && currentLineNumber < lineNumber);
return (currentLineNumber == lineNumber) ? line :
string.Empty;
}
You could use a System.IO.StringReader over your string. Then you could use ReadLine() until you arrived at the line you wanted or ran out of string.
As all lines could have a different length, there is no shortcut to jump directly to line 65.
When you Split() a string you duplicate it, which would also double the memory consumption.
If you have a string instance already, you can use String.Split to split each line and check if line 65 is available and if so use it.
If the content is in a file use File.ReadAllLines to get a string array and then do the same check mentioned before. This will work well for small files, if your file is big consider reading one line at a time.
using (var reader = new StreamReader(File.OpenRead("example.txt")))
{
reader.ReadLine();
}
What you can do is, split the string based on the newline character.
string[] strLines = yourString.split(Environment.NewLine);
if(strLines.Length > lineNumber)
{
return strLines[lineNumber];
}
theString.Split("\n".ToCharArray())[64]
Other than taking advantage of a specific file structure and lower level file operations, I don't think theres any faster way than to read 64 lines, discard them and then read the 65th line and keep it. At each step, you can easily check if you've read the entire file.