How to find a Y value based on X value in 2Dline

Hello, everyone,

I am creating a plot based on several (x,y) value pairs (it constitutes some fuel burn envelope).

Then I have to draw a line parallel to X axis with a given value of X that would start at my plot, which means I have to find a value of Y on my plot

that corresponds to a given X. Or an intersection of my plot and the line parallel to X axis.

I couldn’t find a way to do it.

If somebody can help I’ really appreciate it.

Thanks

I think what you are asking for is interpolation. You have a set of

(x,y) data, and you want to find a new y-value corresponding to a

given x-value.

Take a look at scipy.interpolate.interp1d

import numpy

import scipy

import scipy.interpolate

# Set up fake "data".

x= numpy.arange(10)

y = numpy.sin(x)

# Set up an interpolate object.

interp_func = scipy.interpolate.interp1d(x, y)

# Find the intepolated value of y, given x=3.5.

ynew = interp_func(3.5)

print ynew

Hope that helps,

Roban

## ···

On Fri, Aug 8, 2008 at 2:14 PM, Kazansky, Stella (SKAZANSK) <SKAZANSK@...2122...> wrote:

Hello, everyone,

I am creating a plot based on several (x,y) value pairs (it constitutes some

fuel burn envelope).

Then I have to draw a line parallel to X axis with a given value of X that

would start at my plot, which means I have to find a value of Y on my plot

that corresponds to a given X. Or an intersection of my plot and the line

parallel to X axis.

I couldn't find a way to do it.

If somebody can help I' really appreciate it.

Thanks

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