easy save/load of data in python

Question

What is the easiest way to save and load data in python, preferably in a human-readable output format?

The data I am saving/loading consists of two vectors of floats

Answer 1

As I commented in the accepted answer, using numpy this can be done with a simple one-liner:

Assuming you have numpy imported as np (which is common practice),

np.savetxt('xy.txt', np.array([x, y]).T, fmt="%.3f", header="x   y")

will save the data in the (optional) format and

x, y = np.loadtxt('xy.txt', unpack=True)

will load it.

The file xy.txt will then look like:

# x   y
1.000 1.000
1.500 2.250
2.000 4.000
2.500 6.250
3.000 9.000

Note that the format string fmt=... is optional, but if the goal is human-readability it may prove quite useful. If used, it is specified using the usual printf-like codes (In my example: floating-point number with 3 decimals).