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.
"\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");
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.
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.
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.
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!
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");
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);
}
You could clear the console and then write the new output.
