[Tutor] How to plot amount of lines but the amount is a input

[Alan Gauld]

On 30/12/15 05:55, Tom Xu wrote:
> Dear Pythoneers,
> 
> I want to draw several curves in one graph, but the amount of curves is not
> a fixed number.

OK, But what exactly are you asking us to do?

> My homework is below:
> ---
> import matplotlib.pyplot as plt
> import math
> 
> if __name__=='__main__':
>     try:
>         n=int(input('how many curves? '))
>         ulist=[]
>         thetalist=[]
>         for i in range(n):
>             ulist.append(float(input('Enter velocity: ')))
>             thetalist.append(float(input('Enter angle: ')))
>     except ValueError:
>         print('invalid input')
>     else:
>         generateFr(?????)

You need to put the call to generateFr inside a loop that
iterates n times putting successive values from ulist and
thetalist into the function.


> def generateFr(u, theta):
>     theta=math.radians(theta)
>     g=9.8
> 
>     tflight=2*u*math.sin(theta)/g
>     intervals=frange(0, tflight, 0.001)
>     x=[]
>     y=[]
>     for t in intervals:
>         x.append(u*math.cos(theta)*t)
>         y.append(u*math.sin(theta)*t - 0.5*g*t*t)
>     drawgraph(x, y)
> 
> def frange(start, final, increment):
>     numbers=[]
>     while start<final:
>         numbers.append(start)
>         start+=increment
>     return numbers
> 
> def drawgraph(x, y):
>     plt.plot(x, y)
>     plt.xlabel('x-coordinate')
>     plt.ylabel('y-coordinate')
>     plt.title('Projectile motion')



-- 
Alan G
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