Python - Plot showing Empty

Question

I am trying to plot the following:

#Time
for t in np.arange(1,10,1):
    #Raidus
    for r in np.arange(1,5,1):
        #Velocity in theta direction
        V = C/r*(1-np.exp(-r**2/(4*v*t)))
        print(r,V)
        #Vorticity
        Z = C*((1/(2*v*t))*np.exp(-r**2/(4*v*t))-(1-np.exp(-r**2/(4*v*t)))/r**2)
    
     plt.plot(r,V)

When I print(r,V) python does show 9 tables (each for a different t) with radius from 1-4. However, when I plot, the plot looks completely empty.

Thanks for the help.

Salma El-Sokkary · Accepted Answer · 2021-01-16T14:45:37.523

1

Save the r and the v in two lists. Append the list in each loop with a new r and a new v.

After the interior loop, pass the lists to the plot and empty them.

edited Jan 16 '21 at 14:45

answered Jan 16 '21 at 14:41

Salma El-Sokkary

94
1
10

I tried for the plot to be inside the time loop but outside radius loop. If I put it inside the radius loop, won't it generate a plot for every radius value? Even if I write the plot command after the print command, inside the radius loop, the graph still shows empty. – RSM Jan 16 '21 at 14:44
1

I edited my answer.. problem here is that r and v are not a list, they are just values that are printed in each loop. – Salma El-Sokkary Jan 16 '21 at 14:47
Was the answer helpful? – Salma El-Sokkary Jan 16 '21 at 15:04
1

Yes, thank you. I have turned V, Z and r into arrays, and modified the nested for loop with a variable i. – RSM Jan 16 '21 at 15:20

Python - Plot showing Empty

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