if statement including raw_input just prints whatever i type in to the keyboard

Question

I am very new to python and programming in general and I want to print out the string "forward" whenever i press "w" on the keyboard. It is a test which I will transform into a remote control for a motorized vehicle.

while True:
    if raw_input("") == "w":
        print "forward"

Why does it just print out every key I type?

Answer 1

In Python 2.x the raw_input function will display all characters pressed, and return upon receiving a newline. If you want different behaviour you'll have to use a different function. Here's a portable version of getch for Python, it will return every key press:

# Copied from: stackoverflow.com/questions/510357/python-read-a-single-character-from-the-user
def _find_getch():
    try:
        import termios
    except ImportError:
        # Non-POSIX. Return msvcrt's (Windows') getch.
        import msvcrt
        return msvcrt.getch

    # POSIX system. Create and return a getch that manipulates the tty.
    import sys, tty
    def _getch():
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(fd)
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch

    return _getch

getch = _find_getch()

It can be used like so:

while True:
    if getch() == "w":
        print "forward"