"ValueError: Jahr ist außerhalb des Bereichs" bei der Verwendung von Matplotlib pyplot

Question

Ich versuche, eine Matplotlib-Plotting-Funktion zu erhalten, um einen Graphen mit der X-Achse als eine Zeitachse festgelegt zu erstellen. Wenn ich jedoch versuche, einige Werte gegen UNIX-Zeiten zu plotten, stoße ich auf den Fehler ValueError: year is out of range. Was läuft falsch und wie kann es angegangen werden?

import os 
import time 

import matplotlib.dates 
import matplotlib.pyplot 
import shijian 

def main(): 

    data = [ 
     [1484611200.0, 844.4333], 
     [1484524800.0, 783.3373], 
     [1484438400.0, 774.194 ], 
     [1484352000.0, 769.2299] 
    ] 

    save_graph_matplotlib(
     values  = data, 
     line   = True, 
     line_width = 0.5, 
     title_axis_x = "time", 
     title_axis_y = "value", 
     #time_axis_x = True 
    ) 

def save_graph_matplotlib(
    values    = None, 
    title    = None, 
    title_axis_x  = None, 
    title_axis_y  = None, 
    filename   = None, 
    directory   = ".", 
    overwrite   = True, 
    color    = "black", 
    LaTeX    = False, 
    markers    = True, 
    marker_size   = 1, 
    aspect    = None, 
    line    = False, 
    line_style   = "-", 
    line_width   = 0.2, 
    font_size   = 20, 
    scientific_notation = False, 
    time_axis_x   = False 
    ): 

    # 1D or 2D data 
    if isinstance(values[0], list): 
     x = [element[0] for element in values] 
     y = [element[1] for element in values] 
    else: 
     x = range(0, len(values)) 
     y = values 

    matplotlib.pyplot.ioff() 
    if LaTeX is True: 
     matplotlib.pyplot.rc("text", usetex = True) 
     matplotlib.pyplot.rc("font", family = "serif") 
    if filename is None: 
     if title is None: 
      filename = "graph.png" 
     else: 
      filename = shijian.propose_filename(
       filename = title + ".png", 
       overwrite = overwrite 
      ) 
    else: 
     filename = shijian.propose_filename(
      filename = filename, 
      overwrite = overwrite 
     ) 

    figure = matplotlib.pyplot.figure() 

    if title is not None: 
     figure.suptitle(
      title, 
      fontsize = font_size 
     ) 
    if markers is True: 
     matplotlib.pyplot.scatter(
      x, 
      y, 
      s   = marker_size, 
      c   = color, 
      edgecolors = "none", 
     ) 
    if line is True: 
     matplotlib.pyplot.plot(
      x, 
      y, 
      line_style, 
      c   = color, 
      linewidth = line_width 
     ) 

    # Turn on or off axes scientific notation. 
    if scientific_notation is False: 
     matplotlib.pyplot.gca().get_xaxis().\ 
      get_major_formatter().set_scientific(False) 
     matplotlib.pyplot.gca().get_yaxis().\ 
      get_major_formatter().set_scientific(False) 
    # Set axes titles. 
    if title_axis_x is not None: 
     matplotlib.pyplot.xlabel(title_axis_x, fontsize = font_size) 
    if title_axis_y is not None: 
     matplotlib.pyplot.ylabel(title_axis_y, fontsize = font_size) 
    # Set axes font size. 
    matplotlib.pyplot.xticks(fontsize = font_size) 
    matplotlib.pyplot.yticks(fontsize = font_size) 
    # Set or do not set axis x as time. 
    if time_axis_x: 
     time_formatter = matplotlib.dates.DateFormatter("%Y-%m-%d") 
     matplotlib.pyplot.axes().xaxis_date() 
     matplotlib.pyplot.axes().xaxis.set_major_formatter(time_formatter) 
     matplotlib.pyplot.xticks(rotation = -90) 
    # Set the aspect ratio. 
    if aspect is None: 
     matplotlib.pyplot.axes().set_aspect(
      1/matplotlib.pyplot.axes().get_data_ratio() 
     ) 
    else: 
     matplotlib.pyplot.axes().set_aspect(aspect) 

    if not os.path.exists(directory): 
     os.makedirs(directory) 

    matplotlib.pyplot.savefig(
     directory + "/" + filename, 
     dpi = 700 
    ) 
    matplotlib.pyplot.close() 

if __name__ == "__main__": 
    main() 

Answer 1

Sie benötigen zeitstempel wie x-Daten zu einem Python-Datetime-Objekt zu konvertieren, die dann in matplotlib verwendet werden können, und durch die matplotlib.dates.DateFormatter verstanden werden.

Dies kann mit der datetime.datetime.fromtimestamp() Methode durchgeführt werden.

import datetime 
import matplotlib.dates 
import matplotlib.pyplot as plt 

data = [ 
     [1484611200.0, 844.4333], 
     [1484524800.0, 783.3373], 
     [1484438400.0, 774.194 ], 
     [1484352000.0, 769.2299] 
    ] 

x = [datetime.datetime.fromtimestamp(element[0]) for element in data] 
y = [element[1] for element in data] 

plt.plot(x, y, ls="-", c= "b", linewidth = 2) 
plt.xlabel("Dates") 

time_formatter = matplotlib.dates.DateFormatter("%Y-%m-%d") 
plt.axes().xaxis.set_major_formatter(time_formatter) 
plt.axes().xaxis_date() # this is not actually necessary 

plt.show()