Question

I want to do the following with pyplot and can’t find a way to do it, maybe it’s not possible:

Given a set S of strings and the natural numbers N.
Given a set of items I that are attached a set P of (string € S,number € N) pairs p.
Given a coordinate-system that has S on the y-Axis and N on the x-Axis.

Now I would like to map each pair p in this coordinate-system such that all respective points for a specific item are connected by lines.

Then for each item, I have one graph in this coordinate-system.

One problem is that I have some kind of NULL values if there is a string s € S that is not contained in the pairs attached to a certain item. This should not be interpreted as (s,0) but just ignored…

Say, I have (1) the list L1 of all strings used, (2) an item I1 and (3) an Item I2:

L1 = [London, Paris, Tokio, Berlin, Barcelona, Reykjavik]
I1 = [[London,0],[Paris,10],[Barcelona,23]]
I2 = [Paris,10],[Tokio,19],[Berlin,21],[Reykjavik,23]]

Now I want the I1 and I2 to be mapped into the coordinate-system that has L1 on the y-Axis and the natural numbers on the x-Axis. The “points” of each item should be combined.

I hope it is clear what I mean.

Answer 1

Is this what you want?

from pylab import *

L1 = ['London', 'Paris', 'Tokio', 'Berlin', 'Barcelona', 'Reykjavik']
pos = arange(len(L1))
yticks(pos, L1)

I1 = [['London',0],['Paris',10],['Barcelona',23]]
I2 = [['Paris',10],['Tokio',19],['Berlin',21],['Reykjavik',23]]

I1_y = [L1.index(el[0]) for el in I1]
I1_x = [el[1] for el in I1]

I2_y = [L1.index(el[0]) for el in I2]
I2_x = [el[1] for el in I2]

plot(I1_x, I1_y, 'o-')
plot(I2_x, I2_y, 'x-')
grid(True)
savefig('countries.png')
show()