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python - Controlling GPIO in RPI via python 2 input

问题描述

This is a very simple question that I could not find the answer to via google. I just want to have an input, such as typing Green to turn on a green LED. Here is my code so far.

import RPi.GPIO as GPIO
import time
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(21,GPIO.OUT)
GPIO.setup(26,GPIO.OUT)
GPIO.setup(17,GPIO.OUT)



Green = 'GPIO.output(17, True)'

input ()

Typing in green just says the string back. Without the '', it just runs the script and turns the LED on. Thanks for your hlep.

标签： python

解决方案

You need to capture your input in a variable, like so: color = input()

Then you can plumb that input through some logic:

if color.lower() == 'green':
    GPIO.output(17, True)

Here, I forced the input to be lowercase, so we only account for the input as if it were entered in lowercase, for easy comparison of strings since "Green" != "green"

Because there may still be confusion, I amended this answer with the following two examples:

A more complicated example, using a dictionary:

def set_color_green():
    # Sets green by calling the output function to the gpio object
    GPIO.output(17, True)

# construct a dictionary with valid values
gpio_func_dict = {'green': set_color_green} # Here, all we need is a function name

color = input()

# guard against capital letters
if color.lower() not in gpio_func_dict.keys():
    raise Exception('You provided an invalid option')

# Call the right function
gpio_func_dict[color.lower()]()

And a dangerous example using the string...

if color.lower() == 'green':
    exec(Green) # getting in the habit of doing this could lead to a long career of security flaws, vulnerabilities, and bugs

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