Python 获取用户输入并将输入与字符串进行比较

Question

我正在编写一个程序，用户可以在其中选择一种颜色并使用 Raspberry Pi 点亮所述颜色的 LED。在接受用户输入并尝试将其与颜色进行比较后，我得到 "NameError: name 'red' is not defined"。我该如何解决这个问题？

这是我的代码：

import RPi.GPIO as GPIO
import time

GPIO.setwarnings(False)

#use raspberry pi board numbers
GPIO.setmode(GPIO.BOARD)  

#GPIO output channel
GPIO.setup(7, GPIO.OUT)
GPIO.setup(16, GPIO.OUT)
GPIO.setup(32, GPIO.OUT)
GPIO.setup(37, GPIO.OUT)
GPIO.setup(40, GPIO.OUT)
GPIO.setup(33, GPIO.OUT)
GPIO.setup(13, GPIO.OUT)
GPIO.setup(22, GPIO.OUT)

#get led color
ledColorList = input("What color of light do you want to turn on? Red, green, blue, yellow, or all").split(' ')

#blink function
def blink(pin):
    GPIO.output(pin,1)
    time.sleep(.25)
    GPIO.output(pin,0)
    time.sleep(.25)
    return

if ledColorList[0] == RED:
    blink(7)  

#turn off all pins
GPIO.cleanup()

Answer 1

RED 是一个字符串文字：它应该放在引号之间。

Answer 2

对于 python 2.x 你可以使用 raw_input() 而不是 input() 因为

In Python 2.x, input() expects a Python expression, which means that if you type red it interprets that as a variable named red. If you typed "red", then it would be fine.

Answer 3

我认为你最好将输入强制转换为小写并通过 raw_input:

ledColorList = raw_input("What color of light do you want to turn on? Red, green, blue, yellow, or all").lower().split(' ')

然后对照

检查

if ledColorList[0] == "red":
    blink(7)

Python 获取用户输入并将输入与字符串进行比较

Python getting user input and comparing input to string

python

user-input

led

raspberry-pi