擅长:python、mysql、java
<p>我会用一个专用的精密计时器:</p>
<pre><code>import sys
import time
# a cross-platform precision timer
get_timer = time.clock if sys.platform == "win32" else time.time
distance = 20
input("Press enter to start.")
start_time = get_timer()
input("Press enter to stop.")
stop_time = get_timer()
delta_time = stop_time - start_time # passed time in seconds
speed = distance / delta_time # the unit depends on the unit of your `distance` value
</code></pre>