Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
240 views
in Technique[技术] by (71.8m points)

python - How to incrementally sample without replacement?

Python has my_sample = random.sample(range(100), 10) to randomly sample without replacement from [0, 100).

Suppose I have sampled n such numbers and now I want to sample one more without replacement (without including any of the previously sampled n), how to do so super efficiently?

update: changed from "reasonably efficiently" to "super efficiently" (but ignoring constant factors)

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

If you know in advance that you're going to want to multiple samples without overlaps, easiest is to do random.shuffle() on list(range(100)) (Python 3 - can skip the list() in Python 2), then peel off slices as needed.

s = list(range(100))
random.shuffle(s)
first_sample = s[-10:]
del s[-10:]
second_sample = s[-10:]
del s[-10:]
# etc

Else @Chronial's answer is reasonably efficient.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...