Searching for a Specific Word in a Text File and Displaying the line its on

Question

I am having trouble attempting to find words in a text file in C#.

I want to find the word that is input into the console then display the entire line that the word

Answer 1

How about something like this:

//We read all the lines from the file
IEnumerable<string> lines = File.ReadAllLines("your_file.txt");

//We read the input from the user
Console.Write("Enter the word to search: ");
string input = Console.ReadLine().Trim();

//We identify the matches. If the input is empty, then we return no matches at all
IEnumerable<string> matches = !String.IsNullOrEmpty(input)
                              ? lines.Where(line => line.IndexOf(input, StringComparison.OrdinalIgnoreCase) >= 0)
                              : Enumerable.Empty<string>();

//If there are matches, we output them. If there are not, we show an informative message
Console.WriteLine(matches.Any()
                  ? String.Format("Matches:\n> {0}", String.Join("\n> ", matches))
                  : "There were no matches");

This approach is simple and easy to read, it uses LINQ and String.IndexOf instead of String.Contains so we can do a case insensitive search.

Answer 2

Iterate through all the lines (StreamReader, File.ReadAllLines, etc.) and check if line.Contains("December") (replace "December" with the user input).

Edit: I would go with the StreamReader in case you have large files. And use the IndexOf-Example from @Matias Cicero instead of contains for case insensitive.

Console.Write("Keyword: ");
var keyword = Console.ReadLine() ?? "";
using (var sr = new StreamReader("")) {
    while (!sr.EndOfStream) {
        var line = sr.ReadLine();
        if (String.IsNullOrEmpty(line)) continue;
        if (line.IndexOf(keyword, StringComparison.CurrentCultureIgnoreCase) >= 0) {
            Console.WriteLine(line);
        }
    }
}

Answer 3

For finding text in a file you can use this algorithim use this code in

static void Main(string[] args)
    {
    }

try this one

StreamReader oReader;
if (File.Exists(@"C:\TextFile.txt")) 
{
Console.WriteLine("Enter a word to search");
string cSearforSomething = Console.ReadLine().Trim();
oReader = new StreamReader(@"C:\TextFile.txt");
string cColl = oReader.ReadToEnd();
string cCriteria = @"\b"+cSearforSomething+@"\b";
System.Text.RegularExpressions.Regex oRegex = new 
System.Text.RegularExpressions.Regex(cCriteria,RegexOptions.IgnoreCase);

int count = oRegex.Matches(cColl).Count;
Console.WriteLine(count.ToString());
}
Console.ReadLine();

Answer 4

As mantioned by @Rinecamo, try this code:

string toSearch = Console.ReadLine().Trim();

In this codeline, you'll be able to read user input and store it in a line, then iterate for each line:

foreach (string  line in System.IO.File.ReadAllLines(FILEPATH))
{
    if(line.Contains(toSearch))
        Console.WriteLine(line);
}

Replace FILEPATH with the absolute or relative path, e.g. ".\file2Read.txt".