Deleting a Line in a Text File

How to delete a specific line in a file?

First, open the file and get all your lines from the file. Then reopen the file in write mode and write your lines back, except for the line you want to delete:

with open("yourfile.txt", "r") as f:
    lines = f.readlines()
with open("yourfile.txt", "w") as f:
    for line in lines:
        if line.strip("\n") != "nickname_to_delete":
            f.write(line)

You need to strip("\n") the newline character in the comparison because if your file doesn't end with a newline character the very last line won't either.

Delete or clear a line from a text file

You can open your file in read-write mode and delete the lines that match a condition.

with open(file_path, "r+") as fp:
    lines = fp.readlines()
    fp.seek(0)
    for line in lines:
        if "boop" not in line:
            fp.write(line)
    fp.truncate()

The seek resets the file pointer.

Reference: using Python for deleting a specific line in a file

How can I delete a line from a text file in C++?

Maybe you can just create a new file and put your data into the new file. Like this:

void Data::delete_line(const string& idNr) {
ifstream list;
ofstream outFile("newList.txt");
string readFile, id;

list.open("list.txt", ios::app);

if (list.is_open()) {
    while (getline(list, readFile)) {
        int pos = readFile.find(';');
        id = readFile.substr(0, pos);
        if (idNr != id) {
            outFile << readFile;
        }
    }
}
list.close();
outFile.close();

remove("list.txt");
rename("newList.txt", "list.txt");
}

At the end you just remove your old file and rename the new file with the name of the old file. I hope this will solve your problem.

How to delete a line of text file

This is in winform. textbox1 is where you enter your word and textbox2 will display the message.

textBox2.Clear();
if (!string.IsNullOrWhiteSpace(textBox1.Text))
{
    string LinesToDelete = textBox1.Text;
    var Lines = File.ReadAllLines(@"E:\sample.txt");
    if (Lines.Contains(textBox1.Text))
    {
        var newLines = Lines.Where(line => !line.Contains(LinesToDelete));
        File.WriteAllLines(@"E:\sample.txt", newLines);
        textBox2.Text = "Removed";
    }

    else
    {
        textBox2.Text = "Not found";
    }
}

If you do not need to show the message, the code below will be sufficient.

var Lines = File.ReadAllLines(@"E:\sample.txt");
var newLines = Lines.Where(line => !line.Contains(LinesToDelete));
File.WriteAllLines(@"E:\sample.txt", newLines);

How to delete a line from a text file in C#?

Read the file, remove the line in memory and put the contents back to the file (overwriting). If the file is large you might want to read it line for line, and creating a temp file, later replacing the original one.

How to delete from a text file, all lines that contain a specific string?

To remove the line and print the output to standard out:

sed '/pattern to match/d' ./infile

To directly modify the file – does not work with BSD sed:

sed -i '/pattern to match/d' ./infile

Same, but for BSD sed (Mac OS X and FreeBSD) – does not work with GNU sed:

sed -i '' '/pattern to match/d' ./infile

To directly modify the file (and create a backup) – works with BSD and GNU sed:

sed -i.bak '/pattern to match/d' ./infile

Delete multiple lines from text file using c#

The logic of your current code only deletes the line equal to line_to_delete To resolve you would just need to change your if statement.

if (line_number > 20)  //i would suggest not hardcoding 20
{
    writer.WriteLine(line);
}