Ge Yan
Ge Yan

Reputation: 57

How to show grid line for Y axis in matplotlib

I have a couple of plot scripts that using subplots to generate figure and axis[i].grid(axis = 'y') to show grid only for y-axis. Other works well, but I have no idea why this script doesn't show the grid line. Could someone help me?

import matplotlib.pyplot as plt
import numpy as np
nel   = 8
npts  = 10 
h     = 1./nel

x     = np.zeros((npts+1, nel))
x_c   = np.zeros(nel)
for i in range(0, nel):
    x[:,i] = np.linspace(i*h, (i+1)*h, npts+1)
    x_c[i] = (i+0.5) * h

print(x)
print(x_c)
# 3rd order DGD basis
fig, axs = plt.subplots(2, 1, sharex = True, figsize = (6,10), facecolor = 'w')
plt.tight_layout()
fig.subplots_adjust(hspace = 0)

y = np.zeros((npts+1, nel)) # for 0th element
y[:,0] = (x[:,0] - x_c[1]) * (x[:,0] - x_c[2]) * (x[:,0] - x_c[3])/(-6*h**3)
y[:,1] = (x[:,1] - x_c[1]) * (x[:,1] - x_c[2]) * (x[:,1] - x_c[3])/(-6*h**3)
for j in range(0,nel):
    axs[0].plot(x[:,j], y[:,j], 'r-', linewidth=2)
    axs[0].set_xticks(np.arange(0, 1.01, h))
    axs[0].set_yticks(np.arange(0, 1.2, 1.0))
    axs[0].set_ylim(-0.5, 1.5)
    axs[0].grid(axis = 'y')

y = np.zeros((npts+1, nel)) # for 1st element
y[:,0] = (x[:,0] - x_c[0]) * (x[:,0] - x_c[2]) * (x[:,0] - x_c[3])/(2*h**3)
y[:,1] = (x[:,1] - x_c[0]) * (x[:,1] - x_c[2]) * (x[:,1] - x_c[3])/(2*h**3)
y[:,2] = (x[:,2] - x_c[2]) * (x[:,2] - x_c[3]) * (x[:,2] - x_c[4])/(-6*h**3)
for j in range(0,nel):
    axs[1].plot(x[:,j], y[:,j],'r-', linewidth=2)
    axs[1].set_xticks(np.arange(0, 1.01, h))
    axs[1].set_yticks(np.arange(0, 1.2, 1.0))
    axs[1].set_ylim(-0.5, 1.5)
    axs[1].grid(axis = 'y')

plt.show()

Upvotes: 2

Views: 1006

Answers (1)

Anis R.
Anis R.

Reputation: 6922

Setting the axs[0].grid(axis = 'y') and other axis settings outside the for loop seems to make it work, just tested it in a Jupyter notebook, e.g.:

for j in range(0,nel):
    axs[0].plot(x[:,j], y[:,j], 'r-', linewidth=2)
    axs[0].set_xticks(np.arange(0, 1.01, h))
    
axs[0].set_yticks(np.arange(0, 1.2, 1.0))
axs[0].set_ylim(-0.5, 1.5)
axs[0].grid(axis = 'y')

Upvotes: 2

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