<p>我在这个问题上陷入了困境。这是我的工作代码:</p>
<pre><code>import RPi.GPIO as GPIO ## Import GPIO library
import time ## Import 'time' library. Allows us to use 'sleep'
GPIO.setmode(GPIO.BOARD) ## Use board pin numbering
GPIO.setup(7, GPIO.OUT) ## Setup GPIO Pin 7 to OUT
##Define a function named Blink()
def Blink(kartai):
speed = 1
for i in range(kartai):## Run loop numTimes
print "Iteration " + str(i+1)## Print current loop
GPIO.output(7,True)## Switch on pin 7
time.sleep(speed)## Wait
GPIO.output(7,False)## Switch off pin 7
time.sleep(speed)## Wait
speed = speed - 1/kartai
print "Done" ## When loop is complete, print "Done"
GPIO.cleanup()
kartai = raw_input("Enter length of each blink(seconds): ")
Blink(int(kartai))
</code></pre>
<p>但是,每次迭代LED都会每秒闪烁一次。我认为发生这种情况是因为可变速度被视为<code>int</code>,但是如果我将第7行重写为:</p>
<pre><code>float (speed) = 1
</code></pre>
<p>我得到一个错误:</p>
<blockquote>
<p>can't assign to function call</p>
</blockquote>
<p>在此行中:</p>
<pre><code>print "Iteration " + str(i+1)## Print current loop
</code></pre>