Python while loop replaces variable

Question

if it runs, the figures should print out one by one. k = [3, 4, 5, 6, 2.1, 3.8, 5.5, 7.2] [![enter image description here][1]][1]

but mine figures overwrites each other. so there has to be break or something? [![enter image description here][2]][2]

from matplotlib import pyplot as plt
import numpy as np

def funcx(t, k, r):
    x_1= r(k-1)np.cos(t)
    x_2= r(np.cos((k-1)t))
    x = x_1 + x_2
    return x 
def funcy(t, k, r):
    y_1= r(k-1)np.sin(t)
    y_2= rnp.sin((k-1)t)
    y = y_1 - y_2
    return y 

def plot_function(k, r, string_plot):
    plt.figure()
    plt.plot(x_list, y_list, string_plot)
    ax = plt.subplot()
    ax.axis('off')
    plt.show()


k = [3, 4, 5, 6, 2.1, 3.8, 5.5, 7.2]
r = 5
x_list =[]
y_list=[]



for i in range(0, len(k)):
    for t in np.arange(0, 20*np.pi, 0.001): 
        x_list.append(funcx(t, k[i], r))
        y_list.append(funcy(t, k[i], r))
    plot_function(x_list, y_list, "b")


[![enter image description here][3]][3]


  [1]: https://i.stack.imgur.com/qF3wR.png
  [2]: https://i.stack.imgur.com/t5rS3.png
  [3]: https://i.stack.imgur.com/lmyLL.png

this is how it should be: https://en.wikipedia.org/wiki/Hypocycloid

Answer 1

plot_function(x_list, y_list, "b") it's getting overwritten because of the name given to it "b".

Answer 2

Do this changes to your code. Not sure if it is what you need.

import numpy as np

def funcx(t, k, r):
    x_1= r*(k-1)*np.cos(t)
    x_2= r*(np.cos((k-1)*t))
    x = x_1 + x_2
    return x 
def funcy(t, k, r):
    y_1= r*(k-1)*np.sin(t)
    y_2= r*np.sin((k-1)*t)
    y = y_1 - y_2
    return y 

def plot_function(xlist, ylist,k,ax):
    ax[i].plot(x_list, y_list)
    ax[i].set_title(f'k = {k}')
    ax[i].axis('off')

    #plt.plot(x_list, y_list, string_plot)
    #ax = plt.subplot()
    #plt.axis('off')


k = [3, 4, 5, 6, 2.1, 3.8, 5.5, 7.2]
r = 5
x_list =[]
y_list=[]

#Initialize the subplots before the for loop to avoid the overwriting.
fig, ax = plt.subplots(1,len(k),**{'figsize':(20,4)}) 

for i in range(0, len(k)):
    for t in np.arange(0, 20*np.pi, 0.001): 
        x_list.append(funcx(t, k[i], r))
        y_list.append(funcy(t, k[i], r))
    plot_function(x_list, y_list,k[i],ax)