KEY_DOWN not working in CURSES

Question

I'm building a curses module and using KEY_DOWN to check if a arrow down key is pressed.

But, I get a Name error saying KEY_DOWN is not defined.

if value == KEY_DOWN:

NameError: global name 'KEY_DOWN' is not defined

Answer 1

Good day!

You have to do:

if value == curses.KEY_DOWN:

for it to work.

Hope this works!!!
But if this doesn't work show us your code (so we can analyze it)

Answer 2

To follow up to mvndaai's answer, if you want to detect arrow keys in Python, you have to AND together the three different ASCII values. For example:

    key = getch()
    if key == (27 and 91 and 65):   #27 is ESC, 91 is [, and 65 is A
        print("Up key pressed!")
    if key == (27 and 91 and 66):
        print("Down key pressed!")
    if key == (27 and 91 and 67):
        print("Right key pressed!")
    if key == (27 and 91 and 68):
        print("Left key pressed!")

Answer 3

I am not sure why the yave a gloabl named KEY_DOWN, but if you want a key down, you need to do 3 getchs. Warning, the first getch is the same as an ESC. That means you either make sure it doesn't close on ESC or do a work around like I did below. I also included a chart of what you will get as a getch for each key.

Key
ESC
UP
DOWN
RIGHT
LEFT getch
27
27
27
27
27 getch
 
[
[
[
[ getch
 
A
B
C
D

Which means that when you hit any Arrow key and you are triggering a ESC.

In ruby I tried a work around of checking for 27, then doing a quick timeout on another getch. If that gets a [ it is an arrow or something else, otherwise it is the escape key. Here is my ruby code:

def read_key
  ch = getch
  return check_escape_chars if ch == 27
  ch
end

def check_escape_chars
  require 'timeout'
  begin
    Timeout.timeout(0.0001) {getch}
    case getch
    when "A"; return "UP"
    when "B"; return "DOWN"
    when "C"; return "RIGHT"
    when "D"; return "LEFT"
    end
  rescue Timeout::Error
    return "ESC"
  end
end