CODEWITHSUNDEEP
c#consoleconsole-applicationconsole.writeline
Contango
Contango

Reputation: 80272

Is there a way to delete a character that has just been written using Console.WriteLine?

Is there any way to delete the last character from the console, i.e. 

Console.WriteLine("List: apple,pear,");
// Somehow delete the last ',' character from the console.
Console.WriteLine(".");
// Now the console contains "List: apple,pear."

Sure, I could create a string first then print that to the console, but I'm just curious to see if I can delete characters directly from the console.

Upvotes: 68

Views: 63295

Answers (8)

lidqy
lidqy

Reputation: 2453

If you want to keep on writing into the same line,
overwriting the old line content, not creating a new line,
you can also simply write:

Console.Write("\r"); //CR = 'carriage return' char, moves cursor back to 1st pos in current line, but doesn't add a new one which would do '\n'
Console.Write("{0} Seconds...)", secondsLeft);

So if you want to count down from 10 to 0 then continue if would go like:

for (var i = 10; i > 0; i--)
{
    Console.Write("\r");
    Console.Write("{0} seconds left...{1}", i, i == 1 ? "\n" : "");
    Thread.Sleep(1000);
}

Upvotes: 3

Sámal Rasmussen
Sámal Rasmussen

Reputation: 3495

Console.Write("\b \b"); is probably what you want. It deletes the last char and moves the caret back.

The \b backspace escape character only moves the caret back. It doesn't remove the last char. So Console.Write("\b"); only moves the caret one back, leaving the last character still visible.

Console.Write("\b \b"); however, first moves the caret back, then writes a whitespace character that overwrites the last char and moves the caret forward again. So we write a second \b to move the caret back again. Now we have done what the backspace button normally does.

Upvotes: 56

John Arlen
John Arlen

Reputation: 6689

"\b" is ASCII backspace. Print it to back up one char.

Console.Write("Abc");
Console.Write("\b");
Console.Write("Def");

outputs "AbDef";

As pointed out by Contango and Sammi, there are times where overwriting with a space is required:

Console.Write("\b \b");

Upvotes: 92

nullmn
nullmn

Reputation: 607

To delete a character on the console use

Console.Write("\x1B[1D"); // Move the cursor one unit to the left
Console.Write("\x1B[1P"); // Delete the character

This will properly delete the character before the cursor and move all following characters back. Using the statement below you will only replace the character before the cursor by a white space and not actually remove it.

Console.Write("\b \b");

My proposed solution should work in some other programming languages as well, since it is using ANSI escape sequences.

Upvotes: 8

Luciano Santesso
Luciano Santesso

Reputation: 61

if you want to delete only one char you can use:

Console.SetCursorPosition(Console.CursorLeft - 1, Console.CursorTop); and Console.Write() again.

if you want to delete more than one char, like an automation, you can store the current Console.CursorLeft in a variable and use that value in Console.SetCursorPosition(--variablename, Console.CursorTop) in a loop to delete many chars you want!

Upvotes: 6

aldosa
aldosa

Reputation: 357

The above solutions works great unless you're iterating through a for or foreach loop. In that situation you must use a different approach, like 

 Console.SetCursorPosition(Console.CursorLeft - 1, Console.CursorTop);
 Console.WriteLine(" ");

It does, however work well also for a string join.

Examples:

List<int> myList = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

for (int i = 0; i < myList.Count; i++)
{
    Console.Write(myList[i] + ", ");
}

Console.WriteLine("\b\b"); //this will not work.

foreach (int item in myList)
{
    Console.Write(item + ", ");
}

//this will work:
Console.SetCursorPosition(Console.CursorLeft - 2, Console.CursorTop);
Console.WriteLine("  ");

//you can also do this, btw
Console.WriteLine(string.Join(", ", myList) + "\b\b");

Upvotes: 3

Jeffrey L Whitledge
Jeffrey L Whitledge

Reputation: 59463

This will do the trick if you use Write instead of WriteLine.

Console.Write("List: apple,pear,");
Console.Write("\b");  // backspace character
Console.WriteLine(".");

But you actually have lots of control over the console. You can write to any location you wish. Just use the Console.SetCursorPosition(int, int) method.

Upvotes: 20

Tony Abrams
Tony Abrams

Reputation: 4673

You could clear the console and then write the new output.

Upvotes: 1

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