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

python - pandas DataFrame diagonal

What is an efficient way to get the diagonal of a square DataFrame. I would expect the result to be a Series with a MultiIndex with two levels, the first being the index of the DataFrame the second level being the columns of the DataFrame.

Setup

import pandas as pd
import numpy as np

np.random.seed([3, 1415])
df = pd.DataFrame(np.random.rand(3, 3) * 5,
                  columns = list('abc'),
                  index = list('ABC'),
                  dtype=np.int64
                 )

I want to see this:

print df.stack().loc[[('A', 'a'), ('B', 'b'), ('C', 'c')]]

A  a    2
B  b    2
C  c    3
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 don't mind using numpy you could use numpy.diag

pd.Series(np.diag(df), index=[df.index, df.columns])

A  a    2
B  b    2
C  c    3
dtype: int64

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

...