matplotlib autoscale(axis='y') after slicing plot with set_xlim()

Question

As a demonstration, I\'m plotting x^0 through x^9 with x values in range from 10 to 20.

Then I\'m slicing those images so that I have 9 slices:

x = (10 to 11), (

Answer 1

I solved my issue last night by creating a dictionary with x's as keys and a respective list of y's as values.

This occurs as the data is created by the function y=x**i

in essence I'm creating dictionary structure pseudocode:

data[x0] = [x0y1,x0y2,x0y3....]
data[x1] = [x1y1,x1y2,x1y3....]
data[x2] = [x2y1,x2y2,x2y3....]
etc.

I can later reference all the y values at any given x. From there, find the min and max y value for the left and right side of my slice to manually set ylim. If your xlim slice was more than one x segment wide you'd have to repeat the process for each respective x slice within your xlim. In my instance, my x slices are exactly one segment wide.

import matplotlib.pyplot as plt
import numpy as np

# move my range function out of my data creation loop
x = np.arange(10,20,1)

# create a dictionary of my data with x values as keys
data = {}
for i in range(len(x)):
   data[x[i]]=[]

# create some test data
for i in range(10):
    y = x**i
    plt.plot(x,y,c='red',marker='.',ms=2)

    # store my y data to my data dictionary as its created
    xx = x[-len(y):]
    for j in range(len(xx)):
        data[xx[j]].append(y[j])

# get all x values in chart and reduce to a sorted list set
xd = [] 
for n in range(len(plt.gca().get_lines())):
        line = plt.gca().get_lines()[n]
        xd.append((line.get_xdata()).tolist())
xd = [item for sublist in xd for item in sublist]
xd = sorted(list(set(xd)))

# attempt to plot slices of x with autoscaled y
ax = plt.gca()
for i in range(len(xd)-1):
    ax.set_xlim([xd[i],xd[i+1]])

    # reference my min and max y values by left and right borders of x slice
    ymin = min(min(data[xd[i]]), min(data[xd[i+1]]))
    ymax = max(max(data[xd[i]]), max(data[xd[i+1]]))
    # manually set y limits
    ax.set_ylim([ymin,ymax])

    #eliminate my autoscale call
    #ax.axes.autoscale(enable=True,axis='y', tight=True)
    plt.pause(1) #timing

Now when it plots, y is autoscaled to the x slice, not the entire dataset.