CODEWITHSUNDEEP
pythonpandasmatplotlib
beridzeg45
beridzeg45

Reputation: 426

How to create a graph of function in matplotlib?

I am trying to create a graph of cost function in matplotlib.

Cost function looks like this: image

and the graph should look like this: image

I have written this code to create the graph in matplotlib:

xs=[]
ys=[]
for x in range(1,11):
    y=0.00001*(x**3)-0.003*(x**2)+5*x+1000
    xs.append(x)
    ys.append(y)
tuples=list(zip(xs,ys))
df=pd.DataFrame(tuples,columns=["x","y"])
df.plot(kind="line",x="x",y="y",figsize=(15,5))
plt.show()

and the graph itself looks like this: image

Am I doing anything wrong? How can I get the same distinct shape as in the first graph?

Upvotes: 6

Views: 20546

Answers (1)

creanion
creanion

Reputation: 2763

Use numpy or numpy-like code to make it much easier to write numerical code.

Also, I write 1e-6 here to make sure I use the correct coefficient given by your equation.

import numpy as np

xs = np.linspace(1, 10, 100)
ys = 1e-6*(xs**3) - 0.003*(xs**2) + 5*xs + 1000

plt.plot(xs, ys)
plt.show()

If you want a dataframe, that's ok too:

df = pd.DataFrame({"x": xs, "y": ys})
df.plot(kind="line",x="x",y="y",figsize=(15,5))
plt.show()

Now that the code is simpler, it's easy for you to change the X range and plot the function for another interval - maybe using xs = np.linspace(0, 1500, 100).

enter image description here

Upvotes: 8

Related Questions