<p>这里有一些工作代码,据说注释已经足够多了。你知道吗</p>
<pre><code>sample = [0,0,0,0,2,1,4,1,
432,431,1,4,43,423,45,54534,0,665,765,5687,89870,890,98089,
6,0,1,5,7,3,6,7,8,3,4,4,7,
543,6554,765,768,87234,765876,0,897,987,
0,4,7,4,6,8,0,0,0,0]
def findStreak(data, initial_index, threshold=10, allowed_fluctuation_length=2):
"""Looks for a streak with values all below or all above threshold.
* data: the list to scan.
* initial_index: where to start looking.
* thresold: a value that determines the upper/lower limit of the streak.
* allowed_fluctuation_length: how many values may be beyond threshold
without breaking the streak.
Returns a tuple (start, end), so that data[start : end] is the streak,
or None if initial_index is out of range.
"""
if 0 <= initial_index < len(data):
# determine what kind of streak we want to see
if data[initial_index] > threshold:
belongsToStreak = lambda x: x > threshold # high streak
else:
belongsToStreak = lambda x: x <= threshold # low streak
# scan forward as long as predicate holds
last_good_index = initial_index # where the streak still has not ended
index = initial_index + 1
fluctuation_length = 0 # how many values did not satisfy the predicate
while index < len(data):
if not belongsToStreak(data[index]):
fluctuation_length += 1
if fluctuation_length > allowed_fluctuation_length:
# it was not a fluctuation, it's another streak beginning!
return (initial_index, last_good_index + 1)
else:
last_good_index = index # position under index belongs to the streak
index += 1 # advance
# we ran out of data, but the streak did not seem to end
return (initial_index, last_good_index + 1)
# here initial_index is out of range
# we could omit this; if a function does not return something explicitly,
# it implicitly returns None.
return None
def printStreaks(data=sample):
initial_index = 0
while True:
streak_span = findStreak(data, initial_index)
if not streak_span:
break
initial_index, end_index = streak_span # unpack the tuple
print "Streak is %r, data is %r" % (
streak_span,
data[initial_index : end_index])
initial_index = end_index # advance to next streak
</code></pre>
<p>现在试试<code>printStreaks(sample)</code>,也试试其他列表或阈值。你知道吗</p>
<p>请注意,您的第一个列表包含一个额外的逗号,用于中断解析。你知道吗</p>