Plot 在同一 x 轴上的时间序列的每一年

Question

I have a time series with daily data that I want to plot to see how it evolves over a year. I want to compare how it evolves over the year compared to previous years. I have written the following code in Python:

xindex = data['biljett'].index.month*30 + data['biljett'].index.day
plt.plot(xindex, data['biljett'])
plt.show()

The graph looks as follows: A graph how the data evolves over a year compared to previous years. The line is continuous and and does not end with the end of the year which makes it fuzzy. What am I doing wrong?

Answer 1

From technical perspectives, it happens because your data points are not sorted w.r.t. date, thus it goes back and forth to connect data points in the data frame order. you sort the data based on xindex and you're good to go. to do that: (first you need to put xindex in data dataframe as a new column)

data.sort_values(by='xindex').reset_index(drop=True)

From the visualization perspective, I think you might have several values per each day count, thus plot is not a good option to begin with. So IMHO you'd want to try plt.scatter() to visualize your data in a better way.

Answer 2

I have rewritten as follows:

 xindex = data['biljett'].index.month*30 + data['biljett'].index.day
 data['biljett'].sort_values('xindex').reset_index(drop=True)
 plt.plot(xindex, data['biljett'])
 plt.show()

but gets the following error message: ValueError: No axis named xindex for object type