如何在 plot 中找到给定 y 值的对应 x 值

Question

I now have a plot and a given y value. I would like to find the corresponding x value for the given y value = 209. I tried to use the code here:

x = np.interp(209, ydata, xdata)

But this code doesn't work and always gives me the maximum x value which means nothing.

What should I do for finding the corresponding x value? Thanks in advance for any help!

Answer 1

import numpy as np

def find_x(val, xdata, ydata):
    x = np.where(ydata==val)
    return int(xdata[x])

INPUT:

xdata = np.array([1,3,5,7,9])
ydata = np.array([2,4,6,8,10])

print(find_x(4, xdata, ydata))

OUTPUT:

3