plotting n number of equal points in circular direction in python

August 23, 2022

I am working on the task in which I have to make a circle which is having n number of equal parts. I am provided with centre and radius of the circle which is (0,0) and 4 respectively. To achieve this task, I have written below code,

parts = 36                     # desire number of parts of the circle          
theta_zero = 360/parts
R = 4                          # Radius

x_p = []
y_p = []

n = 0
for n in range(0,36):
    x_p.append(R * math.cos(n*theta_zero))
    y_p.append(R * math.sin(n*theta_zero))

However, after running this code, I got output like below which does not seem a coorect which I am suppose to have.

Kindly let me know what I am doing wrong and give some suggestion of correct code. Thank you

>Solution :

Your circle is weird because math.cos and math.sin accept radians while you are passing degrees. You just need to convert the degrees to radians when calling the math functions.

Like this:

parts = 36         
theta_zero = 360/parts
R = 4 

x_p = []
y_p = []

for n in range(0,36):
    x_p.append(R * math.cos(n*theta_zero /180*math.pi))
    y_p.append(R * math.sin(n*theta_zero /180*math.pi))

Result:

Alternatively changing theta_zero to 2*math.pi/parts would also work and would be slightly faster but it might be a little less intuitive to work with.

Also as @Mad Physicist mentioned you should probably add plt.axis('equal') to unstretch the image.