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
253 views
in Technique[技术] by (71.8m points)

python - Select specific columns in NumPy array using colon notation

I have a 40000 by 60 Numpy array, and I want to sth like this:

mat[:,[0:13,19:23,23:31,39:59]]

Obviously, it does not work. Is there a smarter way to do this than concatenation?

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)

Use np.r_ -

mat[:,np.r_[0:13,19:23,23:31,39:59]]

Sample run -

In [48]: mat = np.random.rand(100,1000)

In [50]: mat[:,np.r_[0:13,19:23,23:31,39:59]].shape
Out[50]: (100, 45)

In [51]: 13+4+8+20
Out[51]: 45

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

1.4m articles

1.4m replys

5 comments

57.0k users

...