Python3.x, Matplotlib: Plotting subplots in a for-loop

Question

I want to make subplots in a for-loop. This is integrated in a larger code. I have multiple csv files containing various x values and fixed y values for all the files. The shape of each file is the same. For instance, it looks like the followings: Data set #1.

y   x1   x2   x3   x4
1  0.2  5.4  3.0  0.7
2  0.1  1.2  4.0  0.6
3  5.0  2.0  2.0  1.8
4  1.2  0.1  0.1  3.8
5  1.0  0.5  0.7  5.8
6  6.5  8.0  0.8  0.8

The x values in each data are complied: my_xdata=[array([0.2,0.1,5.0,1.2,1.0,6.5],[5.4,1.2,2.0,0.1,0.5,8.0],[3.0,4.0,2.0,0.1,0.7,0.8], [0.7,0.6,1.8,3.8,5.8,0.8)]

My desired outcome is subplots plotting x1 and y, x2 and y, x3 and y and x4 and y. But currently, the code is not working. The following is the code that I currently have.

for i in range(len(my_xdata)):
     for a in range(len(specific_x)):
         ax=plt.subplot(4,1,i+1)
         ax.plot(my_y,my_xdata[i])
         ax.set_xlim(15,70)
         ax.axhline(y=0.1, linestyle='--', color='k')
         ax.axhline(y=0.5, linestyle='--', color='k')
         ax.axhline(y=0.9, linestyle='--', color='k')
         ax.axvline(x=median_ten1[a], linestyle='--', color='k')
         ax.axvline(x=median_fifty1[a], linestyle='--', color='k')
         ax.axvline(x=median_ninety1[a], linestyle='--', color='k')
         ax.show()

It doesn't work.

I get the following error message, num must be 1 <= num <= 4, not 5. Any ideas?

specific_x isn't that important, but if you want to know. Here it is:

for i in range(len(my_xdata)):
   f90= interp1d(my_xdata[i], my_y, assume_sorted = False) #interpolate the x values 
   specific_x.append(f90(1.2)) #determine the x values when y is 1.2

Do you mean `plt.subplot(4,1,i+1)`? Also `ax.show()` doesn't exist, just delete it. — ImportanceOfBeingErnest, Oct 12 '19 at 00:09
`41[i]` ??? it's not logical, you need to read the documentation of subplots again — Mohsen_Fatemi, Oct 12 '19 at 00:17
When asking about code that produces an Exception, always include the complete Traceback in the question. Copy the Traceback and paste it in the question, then format it as code (select it and type ctrl-k) — wwii, Oct 12 '19 at 01:45
Useful examples here: https://stackoverflow.com/questions/46615554/how-to-display-multiple-images-in-one-figure-correctly/46616645#46616645 — swatchai, Oct 12 '19 at 02:09

Qvyx · Accepted Answer · 2019-10-12T01:26:44.080

Couldn't reproduce the error message, plotting in subplots with a for loop works quite fine. I used the following code to test:

import numpy as np
import matplotlib.pyplot as plt
from scipy.interpolate import interp1d

my_xdata=np.array([[0.2,0.1,5.0,1.2,1.0,6.5],[5.4,1.2,2.0,0.1,0.5,8.0],[3.0,4.0,2.0,0.1,0.7,0.8],[0.7,0.6,1.8,3.8,5.8,0.8]])
my_y = np.array([10,20,30,40,50,60])

specific_x = []
for i in range(len(my_xdata)):
   f90= interp1d(my_xdata[i], my_y, assume_sorted = False) #interpolate the x values 
   specific_x.append(f90(1.2)) #determine the x values when y is 1.2


for i in range(len(my_xdata)):
     for a in range(len(specific_x)):
         ax=plt.subplot(4,1,i+1)
         ax.plot(my_y,my_xdata[i])
         ax.set_xlim(15,70)
         ax.axhline(y=0.1, linestyle='--', color='k')
         ax.axhline(y=0.5, linestyle='--', color='k')
         ax.axhline(y=0.9, linestyle='--', color='k')
#         ax.axvline(x=median_ten1[a], linestyle='--', color='k')
#         ax.axvline(x=median_fifty1[a], linestyle='--', color='k')
#         ax.axvline(x=median_ninety1[a], linestyle='--', color='k')
         #ax.show()

matplotlib output 4 subplots

Python3.x, Matplotlib: Plotting subplots in a for-loop

1 Answers1