在同一数据框中使用x和y绘制直方图

Question

I'm trying to make a histogram for a dataframe:

Date            d1    d2    h1          h2
2007-01-12      2.0   4.0   0.993508    0.984092        
2007-01-16      7.0   3.0   0.983782    0.977396    
2007-01-17      9.0   8.0   1.016174    0.999694    
...
...

My expected output is to have the d1 and d2 columns on the x axis of the histogram , and the h1 and h2 values be the frequency that gets plotted.

I've looked into plt.hist(), pd.DataFrame.hist() , and np.histogram() but unable to shape the data the way I'd like.

I get errors like len() of unsized object , range parameter must be finite., etc

Answer 1

It sounds like you want a barplot, not a histogram. A histogram typically acts on a collection of data and plots the frequencies for you. If you want to specify the frequencies, how about something like this (assuming you have a pandas.DataFrame called df ):

import pandas
import numpy as np
from matplotlib import pyplot as plt

df = pandas.DataFrame(...)
positions = np.array(df[['d1','d2']]).flatten()
frequencies = np.array(df[['h1','h2']]).flatten()
plt.bar(positions, frequencies)
plt.show()