python plot horizontal line for a range of values

Question

I am really new to python and trying to plot speed as a constant value for the distince from its current startpointinmeters to the next startpointinmeters, so speed is constant from the start to the end (next start).

For example, speed should be 13 for distance 0 to 27.82 and 15 from 27.82 to 40.12 and so on.

Any idea?

startpointinmeters speed
0.0     13.0
27.82   15.0
40.12   14.0
75.33   14.0
172.77  17.0
208.64  18.0
253.0   21.0
335.21  20.0
351.16  25.0
590.38  22.0
779.37  21.0
968.35  22.0
1220.66 20.0
1299.17 19.0
1318.32 14.0
1352.7  9.0

Answer 1

This can be done with the step function of Matplotlib:

import matplotlib.pyplot as plt

x = [0., 27.82, 40.12, 75.33, 172.77, 208.64, 253., 335.21, 351.16,
     590.38, 779.37, 968.35, 1220.66, 1299.17, 1318.32, 1352.7]
v = [13., 15., 14., 14., 17., 18., 21., 20., 25., 22., 21., 22., 20., 
     19., 14., 9.] 

plt.step(x, v, where='post')
plt.xlabel('Position [m]')
plt.ylabel('Speed [m/s]')
plt.show()

Result:

See this example for the difference between the different values for the 'where' argument. From your description it seems you want the 'post' option.