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 was found on in the console.

In my text file I have:

Stephen Haren,December,9,4055551235

Laura Clausing,January,23,4054447788

William Connor,December,13,123456789

Kara Marie,October,23,1593574862

Audrey Carrit,January,16,1684527548

Sebastian Baker,October,23,9184569876

So if I input "December" I want it to display "Stephen Haren,December,9,4055551235" and "William Connor,December,13,123456789" .

I thought about using substrings but I figured there had to be a simpler way.

My Code After Given Answer:

using System;
using System.IO;
class ReadFriendRecords
{
    public static void Main()
    {
        //the path of the file
        FileStream inFile = new FileStream(@"H:\C#\Chapter.14\FriendInfo.txt", FileMode.Open, FileAccess.Read);
        StreamReader reader = new StreamReader(inFile);
        string record;
        string input;
        Console.Write("Enter Friend's Birth Month >> ");
        input = Console.ReadLine();
        try
        {
            //the program reads the record and displays it on the screen
            record = reader.ReadLine();
            while (record != null)
            {
                if (record.Contains(input))
                {
                    Console.WriteLine(record);
                }
                    record = reader.ReadLine();
            }
        }
        finally
        {
            //after the record is done being read, the progam closes
            reader.Close();
            inFile.Close();
        }
        Console.ReadLine();
    }
}

Answer 1

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 2

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".

Answer 3

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.